Why footprint matters more than cell count
Two pieces can use the same number of occupied cells but demand very different space. A straight 5-bar needs a continuous lane, while a large L uses only five cells but occupies a 3×3 footprint. Late-game survival depends on preserving the right geometry, not merely counting empty cells.
Which shapes lose legal placements first?
The 3×3 square, 5-cell bars, 3×2 rectangles and large L corners become dangerous as the board fragments. Small blocks can fit almost anywhere, so spending your only broad region on a tiny piece is often a strategic mistake.
Use the database with Practice Mode
Choose a difficult family here, then open Practice Mode and train the board pattern that supports it. The 3×3 Safety drill is especially useful because protecting a reusable square region also improves placement options for rectangles, corners and T pieces.