The lrepeat command creates a list of size count * number of elements by repeating count times the sequence of elements element .... count must be a non-negative integer, element can be any Tcl value. Note that lrepeat 1 element ... is identical to list element ....
lrepeat 3 a
-> a a a
lrepeat 3 [lrepeat 3 0]
-> {0 0 0} {0 0 0} {0 0 0}
lrepeat 3 a b c
-> a b c a b c a b c
lrepeat 3 [lrepeat 2 a] b c
-> {a a} b c {a a} b c {a a} b c