This one's 250 understandable lines: https://github.com/marijnheule/microsat https://github.com/marijnheule/microsat. You could probably get it to below 200 lin

This one's 250 understandable lines: https://github.com/marijnheule/microsat https://github.com/marijnheule/microsat. You could probably get it to below 200 lines if you removed the restart logic and learned clause compaction, but it's actually a surprisingly competitive solver as is.