How do I create a CSS grid layout box that spans 2 columns and 2 rows?

I have created a grid according to the newest CSS Grid specification but am not familiar with it yet. I am trying to create the following layout without defining grid areas for each child of the grid.

codepen

body {
  max-width: 1024px;
  margin: 10px auto;
}

.grid {
  display: grid;
  grid-gap: 10px;
  grid-template-columns: 1fr 1fr 1fr;
  grid-template-rows: 1fr 1fr 1fr;
  grid-template-areas: "a a b" "a a c" "d e f";
}

.grid__thing {
  background-color: rebeccapurple;
}

.a {
  grid-area: a;
}

.b {
  grid-area: b;
}

.c {
  grid-area: c;
}

.d {
  grid-area: d;
}

.e {
  grid-area: e;
}

.f {
  grid-area: f;
}

img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
      

        
        
        
      

    

<div class="grid">
  <div class="grid__thing a">
    <img src="https://placehold.it/1360x880" alt="" />
  </div>
  <div class="grid__thing b">
    <img src="https://placehold.it/660x405" alt="" />
  </div>
  <div class="grid__thing c">
    <img src="https://placehold.it/660x405" alt="" />
  </div>
  <div class="grid__thing d">
    <img src="https://placehold.it/660x405" alt="" />
  </div>
  <div class="grid__thing e">
    <img src="https://placehold.it/1327x817" alt="" />
  </div>
  <div class="grid__thing f">
    <img src="https://placehold.it/1327x817" alt="" />
  </div>
</div>
      

        
        
        
      

    

Ideally, I would like to be able to set all grid properties on the parent grid item and then ONLY define properties on grid item A to span two columns and rows.

Currently, each grid area is specified and a unique class is added:

.grid {
    display: grid;
    grid-gap: 10px;
    grid-template-columns: 1fr 1fr 1fr;
    grid-template-rows:  1fr 1fr 1fr;
    grid-template-areas: "a a b"
                         "a a c"
                         "d e f";
.a {
    grid-area: a;
}
.b {
    grid-area: b;
}
.c {
    grid-area: c;
}
.d {
    grid-area: d;
}
.e {
    grid-area: e;
}
.f {
    grid-area: f;
}

      

        
        
        
      

    

I would like to do something like this, so I don't need to create a unique CSS class for each grid item:

.grid {
    display: grid;
    grid-gap: 10px;
    grid-template-columns: 1fr 1fr 1fr;
    grid-template-rows:  1fr 1fr 1fr;
    grid-template-areas: "a a b"
                         "a a c"
                         "d e f";
}
.a {
    // The only unique selector, so this is the only thing that
    // should be given unique styling
}