My take on the final level of Playgrounds Learn to Code 1 - Roll Right Roll Left.

RollRightRollLeft.swift

func navAround() {
    if !isBlocked {
        while isOnGem || isOnClosedSwitch {
            if isOnGem {
                collectGem()
            } else if isOnClosedSwitch {
                toggleSwitch()
            }
        }
        moveForward()
    } else if isBlockedLeft && isBlocked {
        turnRight()
    } else {
        turnLeft()
    }
}

while !isOnOpenSwitch {
    navAround()
}