Reckless Technology
Games
Knect 4 v1.0.0Four in a row, against the computer or between two people at one board: drop pucks into a blue upright board and make four across, up or diagonally. Four levels, from one that is easy to beat to one that never loses a game it could save, and five board sizes.
Download
Free, for any use, on as many computers as you like, for Windows, macOS and Linux. The game’s own code is open source under the MIT licence.
To uninstall it: on Windows, Knect 4 in Settings > Apps; on a Mac, Uninstall Knect 4 in /Applications/Reckless Technology, which leaves the other Reckless apps alone; on Linux, sudo apt remove knect4, or delete the unpacked folder.
About the game
Knect 4 is written in C++20, with its window drawn in Skia and its sound made from nothing: each click is a burst of noise a fraction of a millisecond long, the puck’s own ringing a few kilohertz up and the board’s lower knock beneath, a little different every time.
Behind the hardest level is an exact solver after Pascal Pons’s design, with an opening book for the standard board worked out by that solver from the game’s published solution (Allis 1988, Allen 1988). Four in a row on the standard board is a first-player win, and Perfect knows it.
How to play
Move the pointer over a column and your puck hangs above it, with its landing slot marked; click to drop it. The keys work too: 1 to 9 drop into the first nine columns, the arrow keys move the puck along, and Return, space or the down arrow drop it.
The puck falls behind the frame, showing through the holes as it passes, lands with a click and bounces once or twice. The computer’s puck sways above the board while it thinks, then glides to its column and drops. A new game lets the last one’s pucks out: the slider in the frame’s foot opens and they fall out column by column with a clatter.
The four levels
- Easy looks only a move or two ahead. It takes a four it is offered and often stops one, but is otherwise aimless — easy to beat.
- Medium searches up to six plies and is content now and then with a move a little below the best.
- Hard searches twelve plies deep in about two seconds.
- Perfect solves the position exactly where it can — on the standard board from about the eighth puck — and opens from a book worked out by the solver. On the standard board it never loses a game it could have saved.
Hint shows, after a moment’s thought, the column Perfect would play; Undo takes back your last move and the computer’s answer. When a game ends the winning line glows and Play again appears over the board.
Five boards
The board can be 6 × 5, the standard 7 × 6, 8 × 7, 9 × 7, or the supersize 16 × 8. Perfect solves the standard board outright; the larger ones are too big to solve, so it plays them by searching as deeply as its time allows.
Two people at one board
Choose A friend and two people share the board and the mouse: Red and Yellow take turns, the held puck in the colour of whoever is to move, and the panel names them — by the names you type into its Players section, or by colour. First move chooses who starts, and Take turns passes the first move to the other each new game. Games between two people keep a score of their own.
Sound, marks and the window
Every landing clicks, louder the further the puck fell, through your computer’s usual output; Sound turns it off. Marks puts a cross on the red pucks and a star on the yellow, for anyone who cannot tell the colours apart. The View menu sizes the window from 50 % to 150 %.
Everything you choose, and both scores, are kept between launches, in your own settings folder.