Snake Pit

The board is a pit of snakes. The opening at the top stays empty — snakes cannot enter it. Extra empty squares let snakes slide, and let the ladder move left and right as well as up and down. Climb out through the top. Linger too long or spend too many moves, and a snake bites. Each board’s cutoff is the average finish for that board plus a tenth — we do not set the pace. Pick a board, then a level: each level is the same rules with a different starting layout. Later levels start the ladder farther from the opening and mix the snakes more. 3×3 has two levels of loose snakes. 4×4 snakes slide in pairs. 5×5 knots in 2×2 blocks of four — a knot needs two empty squares along the side you push before it can move. 6×6 adds two 2×2 knots and two posts that never move.