function isWalkable(pos, creature, proj, pz)
if getTileThingByPos({x=pos.x,y=pos.y,z=pos.z,stackpo s=0}).itemid == 0 then return false end
if getTopCreature(pos).uid > 0 and creature then return false end
if getTileInfo(pos).protection and pz then return false, true end
local n = not proj and 3...