Lists inside lists — grids, game boards, searching, and patterns
Interactive step-through animation — see how 2D lists are accessed and looped
2D grids, accessing elements, looping, searching, and tic-tac-toe.
Calculate and print the sum of each row in a grid.
Find the largest number in a 2D grid.
Count how many times a value appears in a grid.
Create and print a checkerboard pattern.
Index order, grid creation traps, resetting variables, and debugging.