Simulate a box tilting to the right, causing stones to fall until they hit obstacles or the floor. Re-arrange the characters in a given grid to reflect the resulting state of the box.

On a chessboard, find how many pawns a rook can capture in one move. The rook can move horizontally or vertically until it hits an obstacle or the edge of the board.

You're given an array of numbers. Find how many pairs of numbers in the array satisfy a specific 'nice' property determined by reversing their digits and comparing them.