function isSafe(x: integer, z: integer, w: string):: boolean:
    set {_b} to block at location({_x}, 255, {_z}, world({_w}))
    set {_n} to 0
    while {_b} is air:
        add 1 to {_n}
        set {_b} to block at location({_x}, 255 - {_n}, {_z}, world({_w}))
    if {_b} is water or lava:
        return false
    else:
        return true