Rotating a Three-by-Three Grid
Each cell of a 3 × 3 square tile is coloured black or white. Two tiles are considered the same if one can be rotated in the plane (by 90°, 180° or 270°) to match the other; flipping the tile over is not allowed. How many different tiles are there? Give an integer.
Related problems & prerequisites
Worth solving first
- Two-Color Necklaces 5.0/10
Source: Standard application of Burnside's lemma; no traceable original source. Statement written for AxiomIQ.