ECHO: 1
ECHO: 6
ECHO: 6
ECHO: 2
ECHO: 3
WARNING: Ignoring duplicate variable assignment $a = 4 in file let-tests.scad, line 8
ECHO: 6
WARNING: Ignoring duplicate variable assignment b = 5 in file let-tests.scad, line 9
ECHO: 6
WARNING: Ignoring duplicate variable assignment $a = 4 in file let-tests.scad, line 10
WARNING: Ignoring duplicate variable assignment b = 5 in file let-tests.scad, line 10
ECHO: 6
ECHO: 12
ECHO: 6
ECHO: 12
ECHO: 18
ECHO: [1, 1]
ECHO: [[1, 2], [2, 2]]
WARNING: Assignment without variable name 42 in file let-tests.scad, line 21
WARNING: Assignment without variable name 1 in file let-tests.scad, line 22
WARNING: Assignment without variable name 2 in file let-tests.scad, line 22
WARNING: Assignment without variable name 3 in file let-tests.scad, line 22
WARNING: Assignment without variable name 4 in file let-tests.scad, line 22
