SPICE is a general-purpose, open-source analog electronic circuit simulator. It stands for Simulation Program with Integrated Circuit Emphasis.
ngspice is a successor, and is easily installable on Linux. It’s the simulator I’ve used to explore the Skywater 130 PDK.
Here’s an example spice simulation file that I used to simulate the inverter I drew.
And here’s a nice demo of me showing how a flip-flop works by simulating a Sky130 D type flip flop with SPICE.
I saw that Google was doing the free shuttle service and I thought that would be really cool to get into. I had no idea how to even begin such a process and then I saw the course and it's like “Hey this this is exactly what I need!