Pressure

local function createBlock(x, y, weight, structure, map)
    local block = {}
    block.parent = structure
    block.weight = weight
    block.pressure = 0
    block.map = map
    block.x = x
    block.y = y
    block.updateWeight = function(self)
        self.pressure = self.parent.pressure
        if self.map[self.x] ~= nil then
            if self.map[self.x][self.y] ~= nil then
                local block = self.map[self.x][self.y + 1]
                block:addPressure(block.pressure + self.weigth + self.pressure)
                blobk.parent:update()
            end
        end
    end
    block.addPressure = function(self, pressure)
        self.parent.pressure = self.parent.pressure + pressure
        self.pressure = self.parent.pressure
    end
    block.reload = function(self)
        local x = self.x
        local y = self.y
        local map = self.map
        if map[x] == nil then map[x] = {} end
        map[x][y] = self
        --print("block @ "..x..","..y)
    end
    block.draw = function(self, ox, oy)
        term.setCursorPos(self.x + ox, self.y + oy)
        term.setBackgroundColor(self.parent.col.back)
        term.setTextColor(self.parent.col.text)
        term.write(self.parent.col.char)
    end
    return block
end

local function createStructure(pos, length, dir, map, weight)
    local struct = {}
    for i=1,length do
        local p = {pos[1], pos[2]}
        p[dir] = p[dir] + (i - 1)
        local block = createBlock(p[1], p[2], weight, struct, map)
        struct[i] = block
        --print("Created block "..i)
    end
    struct.length = length
    struct.x = pos[1]
    struct.y = pos[2]
    struct.weight = weight
    struct.map = map
    struct.col = {}
    struct.col.back = colors.white
    struct.col.text = colors.black
    struct.col.char = " "
    struct.pressure = 0
    struct.reset = function(self)
        for i=1,self.length do
            local block = self[i]
            block.weight = self.weight
            block.pressure = 0
        end
        struct.pressure = 0
    end
    struct.update = function(self)
        for i=1,self.length do
            local block = self[i]
            block:updateWeight()
        end
    end
    struct.reload = function(self)
        --print("Reloading..")
        for i=1,self.length do
            local block = self[i]
            block:reload()
        end
    end
    struct:reload()
    return struct
end

local function createMap()
    local map = {}
    map.offset = {0,0}
    map.draw = function(self)
        --sleep(4)
        term.setBackgroundColor(colors.black)
        term.clear()
        term.setCursorPos(1,1)
        for x,ytab in pairs(map) do
            --if type(ytab) == "function" then ytab() end
            for y,block in pairs(ytab) do
                block:draw(map.offset[1], map.offset[2])
            end
        end
    end
    return map
end

local length = 3
local map = createMap()
while true do
    local event, button, x, y = os.pullEvent("mouse_click")
    local struct = createStructure({x, y}, 3, button, map, 10)
    map:draw()
end