-- check a solution placed by player (checker node at pos) and give prizes if correct
local function check_solution(pos, player)
	local meta = minetest.get_meta(pos)
	local sol = meta:get_string('solution')
	if node_is_spec_digit({x=pos.x, y=pos.y+1, z=pos.z}, sol) then
		if meta:get_string('b_saytext') == 'true' then
			minetest.chat_send_player(player:get_player_name(), meta:get_string('s_saytext'))
		end
		if meta:get_string('b_dispense') == 'true' then
			minetest.add_item({x=pos.x, y=pos.y+2, z=pos.z}, meta:get_inventory():get_list('dispense')[1])

		end

        -- make solution node indestructible by students
        minetest.set_node({x=pos.x, y=pos.y, z=pos.z}, {name="teaching:lab"})
	end
end