At times you may want to combine several short lists into a single
longer list. This can be done using the "2D append
function. For example, if you have three variables
"2D x, "2D y and "2D z constructed by the expressions
(def x (list 1 2 3))
(def y (list 4))
(def z (list 5 6 7 8))
then the expression
(append x y z)
will return the list
(1 2 3 4 5 6 7 8).