Drawing Lines on a GUI?

Ok, so I've got my script. Currently, it correctly plots points, but now I want to connect those points to make a line graph. I've tried a lot of different things, but I've not gotten it right. I think the only problem is that the lines have wrong slopes, but I'm not sure if that's the only problem.

PS: If you know of a script that does exactly what I am describing (plotting points and/or drawing lines), then let me know!

Btw, this script uses the data from this table: {18.351, 18.615, 18.516, 18.921, 19.012, 19.051}

local x2 = 0
local y2 = 0
local x1 = 0
local y1 = 0
local dist = 0
local slope = 0
local line = 0

function graph(x, y, i)
    local p = Instance.new("Frame", script.Parent.Pixels)
    p.Size = UDim2.new(0, 5, 0, 5)
    p.Position = UDim2.new(x, 0, y, 0)
    p.BorderSizePixel = 0
    p.BackgroundColor3 = Color3.new(200, 20, 20)
    p.Name = p.Name .. i
    p.ZIndex = 3
    if p.Position.Y.Scale > High then
        High = p.Position.Y.Scale
    end
    if p.Position.Y.Scale < Low then
        Low = p.Position.Y.Scale
    end
    local SpanY = High - Low
    local PixelY = p.Position.Y.Scale
    local FactorY = High - PixelY
    local FractionY = FactorY / SpanY

    local PixelX = p.Position.X.Scale
    local FactorX = (#bux - 1) - PixelX
    local FractionX = FactorX / (#bux - 1)

    local XO = p.Position.X.Offset
    local YO = p.Position.Y.Offset
    p.Position = UDim2.new(FractionX, XO, FractionY, YO)

    --ALL THE CODE ABOVE IS JUST TO PLOT THE POINTS
    --All THE CODE BELOW IS TO MAKE THE LINES

    --So the idea here is to make a new frame, make its height 10 pixels (how thick the line is)
    --and make adjust its length using distance formula, then adjust its rotation using slope form
    --and convert that to degrees. Then make its position the same position as point 1 (which is the top left of the new line, because it is going to the right). Also, X?, Y?, X?, Y? are found by storing each ? and ? into a variable based on if the loop iteration is even or odd. 

    if i%2 == 0 then --So it does "every other" to connect both points when it can only look at one at a time
        y2 = p.Position.Y.Scale * script.Parent.AbsoluteSize.Y
        x2 = p.Position.X.Scale * script.Parent.AbsoluteSize.X
    elseif i%2 == 1 then
        y1 = p.Position.Y.Scale * script.Parent.AbsoluteSize.Y
        x1 = p.Position.X.Scale * script.Parent.AbsoluteSize.X
        slope = math.atan2((y2 - y1),(x2 - x1))
        dist = math.sqrt(math.pow((x2 - x1), 2) + math.pow((y2 - y1), 2))
        line = Instance.new('Frame', script.Parent.Lines)
        line.BorderSizePixel = 0
        line.Size = UDim2.new(0, dist, 0, 10)
        print(slope, slope * 360)
        line.Rotation = slope * 360
        line.Position = UDim2.new(0, x2, 0, y2)
        line.Name = i
    end
end

bux = {18.351, 18.615, 18.516, 18.921, 19.012, 19.051} --Not my actual bux/tix data, but random example

for i = #bux-1, 1, -1 do
    x = i
    y = bux[i]
    graph(x, y, i)
end