Gridcannon is a solitaire game that uses a traditional deck of cards with jokers. The game was made by Tom Francis and Chris Thursten in 2019. In the game you have a 3x3 grid of number cards and around it you have face cards. The face cards are called royals and the goal of the game is to assassinate all 12 of them. If you manage to do this you win the game. Number cards may only be played on matching or lower numbers. In order to kill a royal, you place a card opposite him/her - which means you have lit the charge on a cannon - and you use the two cards between the trigger and the royal, the "payload", to do that much damage. Payloads can include any suits when attacking jacks, but must match the color of any queens attacked and the suit of attacked kings. Aces and jokers provide you with special actions.