The counter was first invented in ancient Greece by the mathematician and engineer Hero of Alexandria. The device is controlled by a counter button on top and a turn handle on the side. These rotate the cylindrical gears with the number 0 to 9 written on them. There are three gears, so this counter can display any number from 0 to 999. The engineering marvel of the device, great for students to learn about, is the Geneva drive that controls the gears. When counting, the drive will increment the next gear when the previous reaches 9. When you need to reset the counter, you can do so by opening the front panel and resetting manually.

This model is rated difficulty level easy and is great for ages 8 and up. It is also certified by STEM.org as an authenticated educational product for helping students learn and develop 21st century skills. For education purposes, the great thing about this model is that it can be made either with or without directions. Given directions, putting together a model like this is a great way to teach procedural direction following and how the machine works. Without directions, assembling the model is like solving a puzzle, activating critical thinking skills.

This model has plenty of fun applications, as many as you can think of. You could count how many steps it takes to get from point A to point B. You could count the number of cars that pass in front of your house in an hour. You could keep the counter on your desk and increment the counter every time a task is completed.