How to Make Solid Matter Out of Pure Electrons

Can you get a bunch of electrons and somehow get them together so they're like stack in them? What does that make? I see what you're saying. Can you build electron crystals? Exactly. And it's a famous physicist Ernest Vigner who about 90 years ago thought about this and he predicted that if you got a lot of electrons together and cooled them down, you also didn't use too many. You could form something called a Vigner crystal, which is matter made out of just electrons.