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