I have created a little program based on an old educational game by Zachtronics (KOHCTPYKTOP: Engineer of the People) named Pharo Chip Designer.
It is an inaccurate and highly simplified tool for the design of silicon chip layouts. Unlike common tools for logic circuits designs, in Pharo Chip Designer, you need to face the real-life problems like propagation delays or limited amount of layers and available substrate area.
It contains levels from the original game, but you can play with your custom designs on larger surfaces. And of course, use all the Pharo power to control the I/O signals.
The Pharo Chip Designer required Pharo 8.0 and Spec2.