I was trying to achieve this kind of UI when I tried implementing the Tic-tac-toe game (I know it looks easy to some XD) Tic-tac-toe board The challenge was how to properly select the first and last column, as well as the first and last row. I seriously did not want to manually remove the borders of the eight cells.

The data structure of my tic-tac-toe grid is not two-dimensional, but one, so I can easily do the tricks below. Think of my counting as this : 0 | 1 | 2 3 | 4 | 5 6 | 7 | 8

For the first row, the top border should be removed, thus: 

.board-item:nth-child(-n + 3) {
    border-top: none;
}

For the last column,

.board div:nth-child(3n) {
    border-right: none;
}

For the first column, 

.board-item:nth-child(3n  - 2) {
    border-left: none;
}

For the last row,

.board-item:nth-child(n + 7) {
    border-bottom: none;
}

And that is it. Thanks for reading. Check my tic-tac-toe game here.

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