with GHDs is the following: any $2$-${\mathrm{GHD}}_k(s,n)$ forms an optimal $2$-$({\mathbf{v}},{\mathbf{k}},1)$ generalized packing, where ${\mathbf{v}}=(n,s,s)$ and ${\mathbf{k}}=(k,1,1)$. The “point set” of the generalized packing is formed from the points of the GHD, together with the row labels and the column labels. Since $t=2$, the only possible admissible triples ${\mathbf{t}}$ are $(2,0,0)$, $(1,0,1)$, $(0,1,0)$ and $(0,1,1)$. The first of these tells us that no pair of points may occur in more than one block of the GHD; the second and third tell us that no point may be repeated in any row or any column; the last tells us that any entry of the $s\times s$ array may contain only one block of the GHD.

In fact, GHDs may be used to obtain $2$-$({\mathbf{v}},{\mathbf{k}},1)$ generalized packings for ${\mathbf{k}}=(k,1,1)$ more generally, for more arbitrary ${\mathbf{v}}$. If ${\mathbf{v}}=(n,r,s)$, we may obtain a rectangular array by (for instance) deleting rows or adding empty columns. Depending on the value of $n$ relative to $r,s$, we may need to delete points and/or blocks. This idea is discussed further in [@packings Section 3.5].

Terminology
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Designs and resolutions
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In this section, we discuss various useful classes of combinatorial designs. For more information on these and related 