Click a tile next to the gap, or use the arrow keys. Order 1 to N with the blank last.
Slide the numbered tiles around the single empty space until they read in order, left to right, top to bottom, with the gap in the bottom-right corner.
💡 Solve it row by row from the top, then column by column on what's left — lock finished tiles in place and never disturb them.
📜 Did you know? Exactly half of all possible tile arrangements are unsolvable. In the 1880s Sam Loyd offered $1,000 to anyone who could swap just the 14 and 15 back into order — an impossible position, so the prize was never claimed.