muderror

minetest.register_node("mud:sandmud_flowing", {
    description = "Flowing Sandmud",
    inventory_image = minetest.inventorycube("mud_sandmud_source.png"),
    drawtype = "flowingliquid",
    tiles = {"mud_sandmud_flowing.png"},
    special_tiles = {
        {
            image="mud_sandmud_flowing.png",
            backface_culling=false,
            animation={type="vertical_frames", aspect_w=16, aspect_h=16, length=1.3}
        },
        {
            image="mud_sandmud_flowing.png",
            backface_culling=true,
            animation={type="vertical_frames", aspect_w=16, aspect_h=16, length=1.3}
        },
    },
    paramtype = "light",
    pointable = false,
    buildable_to = true,
    liquidtype = "flowing",
    liquid_alternative_flowing = "mud:sandmud_flowing",
    liquid_alternative_source = "mud:sandmud_source",
    liquid_viscosity = mud_VISC,
})

minetest.register_node("mud:sandmud_source", {
    description = "Sandmud Source",
    inventory_image = minetest.inventorycube("mud_sandmud_source.png"),
    walkable = true,
    buildable_to = true,
    drawtype = "liquid",
    tiles = {"mud_sandmud_source.png"},
    paramtype = "light",
    liquidtype = "source",
    liquid_alternative_flowing = "mud:sandmud_flowing",
    liquid_alternative_source = "mud:sandmud_source",
    liquid_viscosity = mud_VISC,
})

minetest.register_abm({
    nodenames = {"default:sand"},
    neighbors = {"default:water_source" and "default:air" and "default:sand"},
    interval = 10,
    chance = 1,
    action = function(pos)
        minetest.env:add_node(pos, {name="mud:sandmud_flowing"})
    end
})