Drop Four

Drop Four is a two-player connection game in which the players take turns dropping colored discs into a vertically suspended grid. The pieces fall straight down, occupying the lowest available space within the column.

Be the first player to form an unbroken line of four of your own discs. The line may run:

The board begins empty. Decide who plays first (Red goes first by default).

On your turn, take one of the following actions:

Select one of the seven columns and drop a disc into it. The disc falls due to gravity and rests on top of the highest disc currently in that column (or the bottom of the board if the column is empty). Full columns cannot be selected.

Instead of dropping, you may remove one of your own discs from the bottom row of the board. All discs above it in that column fall down one space, which can create or break connections in surprising ways.

You may not skip your turn — every turn must be either a drop or a pop.

The game ends immediately when a player completes four of their discs in a row (horizontally, vertically, or diagonally). That player wins.

Because a pop shifts an entire column down, it can complete a line for either player. The win always goes to the player whose discs actually form the line of four — not necessarily the player who moved. So a pop that connects four for your opponent loses the game for you, even though you made the last move.

If a single pop completes four-in-a-row for both players at the same time, your opponent wins — you cannot win by connecting your own four if the same move also connects theirs.

If the board fills completely (all 42 discs placed) without a four-in-a-row, the game ends in a draw.