div:nth-of-type(3n+1) { grid-column: 1; } div:nth-of-type(3n+2) { grid-column: 2; } div:nth-of-type(3n+3) { grid-column: 3; } div:nth-of-type(-n+3) { grid-row: 1; }

#ttt > * { border: 1px solid black; border-width: 0 1px 1px 0; display: flex; /* flex styling to center content in divs */ align-items: center; justify-content: center; } #ttt > *:nth-of-type(3n) { border-right-width: 0; } #ttt > *:nth-of-type(n+7) { border-bottom-width: 0; }

print every nth line into a row