<!DOCTYPE html><style>
* {
    border: 1px solid black;
}

.grid {
    display: grid;
    grid-template-columns: 100px 100px;
    grid-template-rows: 100px 100px;
    grid-template-areas: "a b"
                         "a b";
    position: relative;
    width: 200px;
}

.abspos-item {
    position: absolute;
    top: 0;
    left: 0;
    width: 50%;
    height: 50%;
    grid-area: b;
}
</style><div class="grid"><div class="abspos-item"></div></div>