A 3×3×3 cube looks like 27 little cubes, but the middle one is a hidden mechanism. The 26 pieces you can see come in three kinds:

• 8 corners, each with 3 coloured stickers, where three faces meet
• 12 edges, each with 2 stickers, between two faces
• 6 centres, each with 1 sticker, in the middle of a face

Count the stickers to check: 8 × 3 + 12 × 2 + 6 × 1 = 24 + 24 + 6 = 54, which is 6 faces × 9 stickers.