Unlike the previous examples, in this case it is not a single point that determines the mapping figure, but the single arrow from $0$ to $1$, which we designate as $F[1,1]$.

It can also be shown that this single arrow completely determines the function.Thus, given a point / number, $x$, on the source line, there is a unique arrow passing through $x$ parallel to $F[1,1]$ meeting the target line a unique point / number, $x + 1$, which corresponds to the linear function's value for the point/number, $x$.

The single arrow completely determines the function $f$.

Given a point / number, $x$, on the source line,

there is a unique arrow through $x$ parallel to $F[1,1]$

meeting the target line at a unique point / number, $x + 1$,

which corresponds to the linear function's value for the point/number, $x$.