Entries for Weekly Challenge 21 has closed. Thanks to all users who participated.

The winner is @e-pluszak who had pieces connected from opposite sides of the board in just 13 ply: playstrategy.org/8oA69O1a

Users are still welcome to attempt this challenge and post answers here, but the winner has been fixed. The next challenge can be found here: playstrategy.org/forum/weekly-challenges/weekly-challenge-22-cannon-launch