The two-element linear concatenative basis

Brent Kerby calls out that ‘cons’ and ‘sap’ are a linear basis in a concatenative language.

The Theory of Concatenative Combinators » Linear Completeness

[B] [A] cons == [[B] A]
[B] [A] sap  == A B

This is a valid basis because ‘cons’ covers quoting and concatenation, and ‘sap’ covers reordering and unquoting.

Categories of instructions in a concatenative basis

A linear basis for Swanson