{#each ['top', 'bottom'] as edge}
{#each [...Array(horizontalCount).keys()] as n}
= horizontalCount - cornerBlocks}
>
{/each}
{/each}
{#each ['left', 'right'] as edge}
{#each [...Array(verticalCount).keys()] as n}
= verticalCount - cornerBlocks}
>
{/each}
{/each}