ECHO: sum10 = 55
ERROR: Recursion detected calling function 'add_up_to' in file recursion-test-function3.scad, line 5
TRACE: called by 'add_up_to' in file recursion-test-function3.scad, line 5
TRACE: called by 'add_up_to' in file recursion-test-function3.scad, line 5
TRACE: called by 'add_up_to' in file recursion-test-function3.scad, line 5
TRACE: called by 'add_up_to' in file recursion-test-function3.scad, line 5
TRACE: called by 'add_up_to' in file recursion-test-function3.scad, line 5
