The goal of the puzzle is to re-arrange the blocks of squares to get the Red block out the hole at the bottom. Click a block to select it. Use the Arrow keys to move it. The Red block can only move up and down but the others can move in any direction. Note: A block of physically-separated squares (of the same color) move as a single block. Press R to reset a level. All of the (20) levels are possible!
Credit to @danielhal for the source projects (Slides 1-5, all levels are included here). 100% pen. Now with "Best Moves" tracking.
