.parent {
display: grid;
grid-template-columns: repeat(12, 1fr);
grid-template-rows: repeat(12, 1fr);
grid-column-gap: 0px;
grid-row-gap: 0px;
}

.div1 { grid-area: 4 / 4 / 10 / 10; }
.div2 { grid-area: 2 / 5 / 3 / 9; }
.div3 { grid-area: 3 / 2 / 6 / 5; }
.div4 { grid-area: 3 / 9 / 6 / 12; }
.div5 { grid-area: 8 / 9 / 11 / 12; }
.div6 { grid-area: 8 / 2 / 11 / 5; }