-- If executes then first block when condition is true
if true [say 1],
if true [say 2] [say 3],

-- If executes second block when condition is false
if false [say 4] [say 5],

-- If returns nil when without else block
say (if false [say 6]),

-- If returns block execution value
say (if true [7]),
say (if false [say 100, 8] [say 200, 9]),