Colons don't do anything. They are null-operators:
This is equal to:
Global a, b, c
a = 1 b = 2 c = 3
Print a
Print b
Print c
a = 1 b = 2 c = 3
Print a
Print b
Print c
This is equal to:
Global a, b, c
a = 1 : b = 2 : c = 3
Print a
Print b
Print c
a = 1 : b = 2 : c = 3
Print a
Print b
Print c