For example, those single taxpayers with $5,000 of Social Security benefits in the example above would see their marginal tax rate on nonâSocial Security income boosted by 50 percent if their modified AGI was between $25,000 and $30,000 and by 85 percent if their modified AGI was between $34,000 and $36,000.
Three types of vault were commonly used: the barrel-vault, the groined or four-part vault, and the dome. The barrel-vault was generally semi-cylindrical in section, and was used to cover corridors and oblong halls, like the temple-cellas, or was bent around a curve, as in amphitheatre passages.
Another type of siege weapon was the trebuchet, which is a form of catapult, but the power source was different. The trebuchet used gravity and weights to hurl the projectile. The catapult used in the Middle Ages was powered by one of four different sources. These were tension, torsion, traction, and gravity. Let's take a closer look at each power source and how it worked.