Aligning the Grid

I walked past the swings to the low playground activity frame. Mounted between two green steel posts was a tic-tac-toe grid of nine rotating yellow plastic cylinders. I climbed onto the lower horizontal support bar to inspect the middle tier. The center cylinder was resting halfway between an embossed 'X' and 'O'. Bracing one boot against the frame upright, I gripped the ridged outer edge of the block with my free hand and applied upward torque. The cylinder spun on its metal axis with a hollow plastic clatter before clicking flush on a crisp red 'O'. All three symbols across the row now align.