As well as a size reference for several components, the front is a functioning circuit if populated. The LEDs will light up when you press the tactile switches and you can put it into an LED tester mode to check the polarity of LEDs.The back is just component footprints, some animal footprints and some ants. The whole thing is in a frame with a v-score on one side and mouse-bites on the other so you can show someone what they look like once broken out. https://kitspace.org/boards/github.com/kitspace/ruler/