I received an old terracotta pot with some succulents a while back that also had some clovers growing in it. One day I noticed a 4-leaf clover, then another, any another all in the same pot. The next day my black cat had eaten them all, but that’s another story. Two years later and the same pot still regularly produces 4-leaf clovers while the other nearby pots only seem to ever produce the normal 3-leaf variety.