Friction and Leverage

I stepped down from the metal rail to examine the lower level. A wooden coaster lay askew near the coffee table leg, resting atop a thick braided rug. I planted one foot on the wood and pressed down. The coaster tipped upward at an angle of roughly twenty degrees. I tested the edge with my hand, observing the gap beneath. By sliding a fallen wooden matchstick under the raised rim, the tilt remained fixed without my weight. The balance holds. It functions as a stable wedge.