remove letter from 1 letter from a Variable (Solve)

ok guys in game play

3 instance

txtAobj = C

txtAobj = A

txtAobj = T

Variable Text =""

on touch txtAobj - system add to Var Text txtAobl.Text

run i touch C then A then T

Debug.log = Variable Text = CAT

How do i Remove the last letter added to the variable example 1 remove T then remove A then remove C

here the .capx file

drive google com/open?id=0B0MCCeWLbpwYcndpX1o2ZVhBV2s

Variable1 = left(Variable1, len(Variable1)-1)

blackhornet

thank you