This is a picture of Swiss coins; from left to right and top to bottom: 5 CHF, 2 CHF, 1 CHF, 0.5 CHF, 0.20 CHF, 0.10 CHF, 0.05 CHF, and then again 0.10 CHF, just under 0.5 CHF. The reason for this alignment should be clear: 50 cents (centimes) of franc is smaller than the coins of 10 and 20 cents of franc. It is also lighter than them: ½ franc weighs 2.2 g, while 10 cents weigh 3 g and 20 cents weigh 4 g.
If we remove the ½ CHF coin, we have increasing diameters, thickness (with one small exception from 0.20 to 1 CHF) and weights as we expect.
The logic behind this choice is a little mistery to me; I keep undervaluing that coin, thinking that it's the 10 centimes coin. They forgive me, though… after all I'm only a tourist in this land.