Below are photos of two pairs of Urgos gears (circa 1985: modern, mass-produced parts). You can see how the teeth interact when the depthing is too deep, (approximately) correct, or too shallow. Notice also the difference in the size and tooth count of the larger pinion. The last two photos are from an Omega 551 (circa 1960) and a Rolex 1570 (circa 1969) wristwatches.
