Repeatedly evaluates the
instructionlist as long as the evaluated
conditionlist remains FALSE.
instructionlist may not be run at all.
conditionlist input must contain an expression that evalautes to either TRUE or FALSE.
The fact that the
conditionlist input is a list may be misleading, because it should contain exactly one expression.
It is only a list because the contents of a list are not evaluated by default.
Instead, they must be explicitly evaluated with RUN.
This allows Logo to reevaluate
conditionlist after each iteration, rather than only evaluating it once.
MAKE "i 0 UNTIL [:i>3] [MAKE "i :i+1 PRINT :i]1 2 3 4