Swash Chess so named because of it’s vague resemblance to a swashtika is a 64 square variant with a hollow center that pieces can move around but not through.
Pieces are orthodox minus Queens and two Rooks pawns and move the same as orthodox chess. The Queen’s Bishop and Knight have swapped positions so Bishops cover both square colors. The central space acts as a barrier for the Queens and the two open Rooks have no facing opponents. Of interest here is how the Kings and Queens meet up diagonally. Also Kings, Queens and open Rooks can move straight away.
Pawns still move as orthodox, one forward with option of two on the first move and take one square diagonally as well as retrieve taken pieces upon reaching the opponents side of the board.
Above is a variation on the theme with 64 squares and four hollow spaces in the center.
Queens, Queens Bishops, King’s Knights and Rooks are free to move straight away in this variant.
Above is the other possible variation in the series with only the four pawns. The Queen’s Bishop and Knight are swapped to facilitate having Bishops on both square colors. Queens and Bishops hold more sway as the board becomes extremely diagonal. The King is open to attack straight away from the Queen and there is only the one move possible out of check.