This package consists of 3 datatypes: Wedge, Can, and Smash.
You can imagine these three types as Maybe (Either a b), Maybe (Either a (Either b (a,b)), and Maybe (These a b) respectively. It turns out that that each of these datatypes has spcial properties:
the Wedge datatype represents the coproduct (like, Either) in the category Hask* of pointed Hask types, called a wedge sum. One can derive this by noting that units are the same in Haskell, and the sum of two pointed types is (1 + a) + (1 + b) ~ 1 + a + b ~ Wedge a b.
the Can datatype represents the product (like, (,)) in Hask*. You can derive this by considering the product of two pointed types (1 + a) * (1 + b) ~ 1 + a + b + a*b ~ Can a b.
the Smash datatype represents a special type of product, a
smash product, in the category Hask*. The smash product is a symmetric, monoidal tensor in Hask* that plays nicely with the product, ‘Can’, and coproduct, ‘Wedge’.
Pictorially, these datatypes look like this:
'Can':
a

Non +++ (a,b)

b
'Wedge':
a

Nowhere ++

b
'Smash':
Nada ++ (a,b)