As I am luck deficient to actually do still life syntheses, I will make a theoretical statement: for any n-cell still life where n is at least 9, there exists a glider synthesis at the cost of (n-5) gliders. Let's see how at the time of writing the reality deviates from that:
- All 9-cell still lives except xs9_178426 and xs9_31248go have a 4-glider synthesis each.
- All 10-cell still lives have a 5-glider synthesis each.
- All 11-cell still lives except xs11_321eg8o have a 6-glider synthesis each.
- All 12-cell still lives have a 7-glider synthesis each.
- All 13-cell still lives have an 8-glider synthesis each.
- All 14-cell still lives except xs14_dbgzw1qm have a 9-glider synthesis each.
- All 15-cell still lives except 18 in this post have a 10-glider synthesis each.
- All 16-cell still lives except 297 have an 11-glider synthesis each.
- All 17-cell still lives except 1106 have a 12-glider synthesis each.
...
As time goes by, the statistics can be incrementally changed by doing individual syntheses, or dramatically changed if people like AGreason keeps running transfer.py for optimization.