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For building arch shapes, you can use either tapered/wedge-shaped bricks or standard rectangular bricks. Tapered bricks are specially designed for arches to create uniform mortar joints, while rectangular bricks can be used for a flatter arch, sometimes called a soldier arch. Special shapes like double-tapered arch bricks or bricks with a specific angle (like a 70° skew-back angle for flat arches) are also available for curved elements.
Types of bricks for arches
Tapered or wedge-shaped bricks:
These are the most common for rounded arches. They are tapered to ensure that the mortar joints are of a consistent thickness throughout the depth of the arch.
Double-tapered arch bricks: These are double-tapered in either width or length to form curved features, like an archway or a circular window.
Rectangular bricks (cut or full-size):
Soldier arches:
These are created by placing standard rectangular bricks on their ends, with their long sides set vertically. This type is more of a flat arch and requires support like a lintel or frame.
Flat arches:
Flat arches are often constructed with standard rectangular bricks that are the same size and have parallel sides, sometimes with a specific skew-back angle.
Specialty and pre-fabricated arches: Modern technology allows for pre-fabricated brick arches built to specific dimensions and designs, which can be a cost-effective solution.
Key considerations for size and shape
Uniformity:
The key for most arches is achieving uniform mortar joints for structural integrity. Tapered bricks achieve this, while flat arches often use standard rectangular pieces with a consistent, small mortar joint.
Angle:
For flat arches, a 70° skew-back angle is common for the voussoirs (the wedge-shaped stones used to build the arch).
Customization:
If your design requires specific angles, curves, or a certain rise, you may need to specify custom dimensions or use pre-fabricated arches

The Raptor engine is designed to create a thrust of 507,000 pound-force (lbf).
The SpaceX Raptor engine operates on a sub-cooled mixture of liquid methane (CH4) and liquid oxygen, which has a high boiling point and is neither toxic nor corrosive, making it safer and more straightforward to store than conventional fuels
The Raptor engine has possibly the highest chamber pressure of any rocket engine. In 2019, the engines achieved a chamber pressure of 257 bar, equivalent to over 3,700 pounds-force per square inch (psi). In 2023, that record was obliterated by the Raptor V3, which achieved 350 bar (over 5,000 psi).
Raptor engine's specific impulse was 350 or 380 seconds, depending on the nozzle,

Meanwhile, the Blue Origin BE-4 is produces 550,000 lbf.
The Blue Origin BE-4, in contrast, uses a liquified natural gas (LNG) and liquid oxygen combination.

While a single BE-4 engine outperforms an individual Raptor engine, the SpaceX Super Heavy first-stage booster has more overall thrust because it uses 33 Raptor engines to provide an explosive 16.7 million pounds of thrust.
Comparatively, the BE-4 lags behind by an ever-widening margin. In 2016, the BE-4 achieved a pressure of 134 bar (1,950 psi).
In contrast, the New Glenn's comparatively scant set of seven BE-4 engines produces 3.85 million pounds of thrust for its booster.
whereas Jeff Bezos stated that the BE-4's specific impulse was around 340 seconds.

The Raptor engines utilize a full-flow staged combustion, and the BE-4 an oxygen-rich staged combustion. Both are forms of "staged combustion," where the propellant travels through several chambers and combusts in stages. This method is mechanically complex, converting space fuel into astonishing levels of thrust, along with highly pressurized and searing exhaust. Oxygen-rich combustion cycles burn a small amount of fuel along with a large amount of oxidizer in the preburner. In contrast, a full-flow engine has multiple preburners: one for the oxygen-rich combustion cycle and another for burning a small amount of oxidizer with a lot of fuel. While more complex than oxygen-rich staged combustion engines, full-flow staged engines operate at cooler temperatures and lower pressures, resulting in a longer lifespan.

Several major US businesses failed in the 1990s due to factors like increased competition, failure to adapt to market changes, and poor management, including the iconic department store chain Woolworth's and PC manufacturer Compaq. Other notable failures include the defunct toy retailer KB Toys and Frito-Lay's fat-free "WOW! Chips" line, which failed due to digestive side effects.
Retail and department stores
Woolworth's: Faced increasing competition from stores like Walmart and Target, leading to the closure of its U.S. five-and-dime stores in 1997 before the parent company rebranded as Foot Locker.
KB Toys: Went bankrupt and vanished due to competition from big-box retailers and the rise of e-commerce.
Gantos: A women's clothing chain that filed for bankruptcy and liquidated its stores by the end of the decade.
Technology
Compaq: Once the largest PC supplier, it faltered due to product quality issues and an inability to keep up with low-cost competitors like Dell. The company was eventually acquired by Hewlett-Packard in 2002.
Etoys.com: An early online toy store that collapsed when the dot-com bubble burst.
Tiger Electronics: Its "Arzone" portable gaming device failed due to its blurry screen and clunky gameplay.
Food and drink
Frito-Lay WOW! Chips: The "fat-free" chips, made with Olestra, caused severe digestive issues for many consumers, leading to the product's failure.
Zima: This clear, carbonated malt beverage was marketed as a sophisticated alternative to beer but failed to gain traction with consumers.
Other
Blockbuster Video: While its collapse occurred in the early 2000s, its failure to adapt to streaming and buy Netflix was rooted in the 1990s, making it a notable example of a 90s-era business failing to look ahead

Several major US businesses failed in the 2000s due to issues like accounting scandals, failure to adapt to new technology, and a lack of innovation. Prominent examples include Enron and WorldCom (accounting fraud), Blockbuster and Polaroid (failure to adapt to digital streaming and photography, respectively), and the dot-com bubble failures like Pets.com and Webvan.
Failed due to accounting scandals
Enron: Once a leading energy company, its collapse in 2001 was one of the largest accounting scandals in history, says the FBI.
WorldCom: The telecommunications giant also collapsed due to a massive accounting scandal in 2002.

During the 2010s, many long-standing US businesses failed due to a combination of new technology, shifting consumer behavior, and heavy debt. The "retail apocalypse" was a primary driver, as e-commerce giants like Amazon displaced traditional brick-and-mortar stores.
Prominent failures in the 2010s
Retail
Toys "R" Us: Filed for bankruptcy in 2017 and closed all US stores in 2018. It struggled to compete with Amazon and Walmart and was burdened with massive debt from a leveraged buyout in 2005. The brand later attempted a comeback with a smaller footprint.
Sears Holdings Corp: The parent company of Sears and Kmart filed for bankruptcy in 2018. The iconic department store chain suffered a slow decline from intense competition from big-box and online retailers.
Borders: The bookstore giant filed for bankruptcy in 2011 and liquidated its remaining stores. It failed to adapt to the shift to online bookselling and e-readers, leaving its customers and website to its competitor, Barnes & Noble.
Payless ShoeSource: The discount shoe retailer filed for bankruptcy in 2017 and 2019, closing all 4,400 stores across 30 countries. It was unable to compete with online retailers and other discount stores.
RadioShack: Known for electronics and batteries, RadioShack filed for bankruptcy twice during the decade (2015 and 2017). It was a victim of changing tech trends and fierce online competition.
The Bon-Ton: The regional department store chain, which operated stores like Carson's and Younkers, filed for bankruptcy in 2018 and liquidated after not turning a profit since 2010.
American Apparel: The clothing retailer filed for bankruptcy in 2015 and 2016, weighed down by debt and sales declines. The brand now operates as an online-only business.
Entertainment
Blockbuster: The video rental chain, which once had over 9,000 stores, filed for bankruptcy in 2010. The company failed to adapt to the new competitive landscape of Netflix, Redbox kiosks, and streaming services.
Movie Gallery: This competitor to Blockbuster and parent of Hollywood Video filed for bankruptcy in 2010, resulting in the closure of all its 2,400 US locations.
Technology and others
Theranos: The blood-testing startup, founded by Elizabeth Holmes, was one of the most high-profile tech failures of the decade. The company, which was valued at $9 billion at its peak, dissolved in 2018 after it was exposed as fraudulent.
Eastman Kodak Co.: The film photography giant filed for Chapter 11 bankruptcy in 2012. The company, which invented the first digital camera, failed to capitalize on the digital revolution and was a "corporate America poster child" for a company that resisted transition.
BlackBerry: Once a leader in mobile devices, BlackBerry's popularity waned in the 2010s due to its slow adoption of touchscreen technology and app ecosystems. The company exited the smartphone business in 2016 to focus on cybersecurity.
Hummer: The SUV brand was discontinued in 2010 after parent company General Motors filed for bankruptcy the year before. The brand fell out of favor following the 2008 oil price spike and a shift toward fuel-efficient vehicles

Many US businesses failed in the 2020s, especially during the initial COVID-19 pandemic, including retailers like J.C. Penney, Neiman Marcus, J. Crew, and Brooks Brothers. Other significant failures included Bed Bath & Beyond, which went bankrupt in 2023, and Pier 1 Imports, Modell's Sporting Goods, and Art Van Furniture, which all filed for bankruptcy in 2020. Financial institutions like First Republic Bancorp and SVB Financial Group also failed.
Major retail bankruptcies in the 2020s
Bed Bath & Beyond: Filed for bankruptcy in 2023.
J.C. Penney: Filed for bankruptcy in 2020.
Neiman Marcus: Filed for bankruptcy in 2020.
J. Crew: Filed for bankruptcy in 2020.
Pier 1 Imports: Closed all stores after filing for bankruptcy in 2020.
Modell's Sporting Goods: Filed for bankruptcy in 2020.
Art Van Furniture: Filed for bankruptcy in 2020.
Brooks Brothers: Filed for bankruptcy in 2020.
Tuesday Morning: Filed for bankruptcy in 2020.
Sur La Table: Closed many stores during its 2020 bankruptcy process.
Lord & Taylor: Filed for bankruptcy in 2020.
Financial sector failures
First Republic Bancorp: Failed during the banking turmoil in 2023.
SVB Financial Group: Failed during the banking turmoil in 2023

Since 2020, the U.S. has experienced a historic surge in new business applications, with record-breaking numbers filed in 2021 and 2023. This sustained period of high business creation is a significant shift from previous decades and was primarily driven by pandemic-induced disruptions and a changing labor market.
New business applications per year
Data based on information from the U.S. Census Bureau.
Year     Business Applications    Change vs. Prior Year    Notes
2020    4.4 million    +24.5%    A sharp increase during the first year of the pandemic, with applications soaring 51% higher than the 2010–2019 average.
2021    5.4 million    +23.5%    A new annual record for business applications, largely influenced by pandemic-era economic and labor shifts.
2022    5.0 million    -6.0%    A slight dip from the 2021 peak, but applications remained well above pre-pandemic levels.
2023    5.5 million    +8.1%    The highest number of new business applications ever recorded in a calendar year.
2024    5.21 million    -4.77%    A moderation from the 2023 peak, though still a period of robust entrepreneurship.
2025    Projected millions    +3.15% (partial data)    As of August 2025, over 3.5 million applications had been submitted, indicating that a high level of business formation is continuing.
Key drivers and characteristics of the boom
Pandemic as a catalyst: The COVID-19 pandemic fueled entrepreneurship by necessity, as many people who lost their jobs started their own businesses.
Shift in work: The rise of remote work and the gig economy gave people more flexibility to pursue entrepreneurial ventures.
Growth in specific sectors: Initial growth was most significant in sectors that supported the "home-based economy," such as e-commerce (retail trade), transportation, and personal services.
Increased diversity: New entrepreneurs in the 2020s have been more diverse than in the past, with women, Black, Asian, and Hispanic shares of self-employed Americans near all-time highs.
Mix of high and low-propensity businesses: The surge included both "high-propensity" businesses, which are likely to hire employees, and a large number of sole proprietorships and ventures less likely to have a payroll.
Long-term outlook
This era of heightened business creation marks a new, higher "plateau" for entrepreneurship in the United States. The surge has proven to be more than a temporary blip, representing a lasting shift in the country's economic landscape

The 1960s saw the rise of new businesses in various sectors, including fast food franchises like Domino's Pizza and the first discount retailers such as Kmart, Walmart, and Target. The decade was also characterized by the growth of large conglomerates, the development of shopping centers, and the establishment of tech and service companies like Medtronic, Dolby Laboratories, and Instinet.
Retail and consumer goods
Discount Retailers: Kmart was the first, opening in 1962, followed by Walmart and Target in the same year, which introduced a new model of bulk purchasing to offer lower prices.
Franchises: The franchise boom was in full swing, with chains like Domino's Pizza, McDonald's, and Holiday Inn expanding rapidly.
Shopping Centers: More than 8,000 shopping centers were built during the decade, changing how and where people shopped.
Technology and services
Tech and Manufacturing: Companies like Medtronic, Teradyne, and Dolby Laboratories were founded.
Financial Services: NationsBank, Duane Reade, and Jackson Hewitt were among the new financial and service businesses.
Logistics and communication: Sea-Land Service pioneered containerized shipping, and Instinet launched an electronic system for institutional investors.
Conglomerates and hospitality
Conglomerates: A wave of business acquisitions led to the formation of large, diversified conglomerates like ITT Corp. and Litton Industries.
Hospitality: New hotels were built to accommodate the growing population, and new restaurant chains emerged, such as the Playboy Club

he 1970s saw the establishment of many new US businesses, particularly in the tech sector with the rise of semiconductors and venture capital firms like Sequoia Capital and Kleiner Perkins. Other notable companies started in this decade include retail giants like Days Inn, Chili's, and Chi-Chi's; technology and software companies such as Atari and Microsoft; and others like Intel and Acadian Ambulance. The business landscape also reflected broader societal changes, with the emergence of niche stores catering to specific subcultures, such as record stores and boutiques.
Technology and computing
Intel: A major player in the semiconductor industry, which saw significant growth in memory products like the Intel 1103 DRAM.
Microsoft: Founded in 1975 by Bill Gates and Paul Allen.
Atari, Inc.: Founded in 1972, it became a major force in the video game industry.
Venture capital firms: The decade saw the founding of Silicon Valley's top venture capital firms, such as Sequoia Capital and Kleiner Perkins Caufield & Byers, both established in 1972.
Retail and services
Days Inn: A hotel chain that began in the 1970s.
Chili's and Chi-Chi's: Two popular restaurant chains that were established during this period.
Apple Computers: Though not a business startup in the 1970s, the company was founded in 1976.
Specialty stores: A rise in niche stores, including record stores and boutiques, reflected the segmentation of the market and counterculture movements.
American Home Shield: A company that was established in 1971.
Other notable businesses
Amdahl Corporation: A computer company established in the 1970s.
Acadian Ambulance: A company that was established in 1971.
DeLorean Motor Company: A car company established in 1975

The 1980s saw the establishment of many new US businesses, spanning various sectors like technology, retail, and direct sales. Notable tech companies founded during this decade include Adobe Inc. and Synnex. Retail and service-based companies like The UPS Store and ShowBiz Pizza Place also emerged. The direct selling industry experienced significant growth, with companies like Herbalife and The Pampered Chef being founded in the 1980s.
Technology and software
Adobe Inc.: A company that would become a giant in the software industry.
Synnex: A technology services company.
Access Software: A video game developer.
Symbolics: A computer company specializing in Lisp machines.
Retail and food service
ShowBiz Pizza Place: A family entertainment center and restaurant chain.
The UPS Store: A retail franchise focused on packing and shipping services.
Amy's Kitchen: A company that prepares and sells frozen organic meals.
Sierra Nevada Brewing Co.: A craft brewery.
Direct sales
Herbalife: A company that sells nutrition, weight management, and skincare products.
The Pampered Chef: A company specializing in kitchen tools.
Nu Skin: A company in the beauty and wellness sector.
Stampin' Up!: A company focused on paper crafting supplies.
Other sectors
Aéropostale: An American lifestyle clothing company.
Airgas: A distributor of industrial gases.
American Graphics Institute: A company providing design and technology training