What is the difference between these two mouse properties?

I've read the description on the wiki of the Mouse.Hit Property and I understand it perfectly.

However, after reading the description of the Origin I didn't quite understand what it was saying.

I created this code as an attempt to understand it but I still didn't get it.

script.Parent.Equipped:connect(function(M)
	M.Move:connect(function()
		print(M.Origin.X)
		print(M.Hit.X)
		wait(5)
	end)
end)

This is inside a local script within a tool.

My overall intent is to create a BASIC dropper tool that only works over a given base. This is what I have so far.

--Sets up the array for taken spaces
avaliableSpaces = {}
for avSet=0,15 do
	avaliableSpaces[avSet] = {}
end

--Sets all values on the board to zero
for row=0,14 do
	for column=0,14 do
		avaliableSpaces[row][column] = 0
	end
end

--Used to check and see if a space is taken
function checkAvaliablity(x,z)
	--Gets area code for x and z values
	x = math.floor((x + 30)/4)
	z = math.floor((z + 30)/4)
	if(avaliableSpaces[x][z] == 0) then
		return true
	end
	return false
end

script.Parent.Equipped:connect(function(M)
	--Creating the invisible brick 
	xy = Instance.new("Part", game.Workspace)
	xy.Size = Vector3.new(4,4,4)
	xy.Anchored = true
	xy.CanCollide = false
	xy.Transparency = 0.5
	xy.Name = game.Players.LocalPlayer.Name.."Brick"
	xy.CFrame = game.Workspace.Base.CFrame:toWorldSpace(CFrame.new(0,2.5,0))
	yx = Instance.new("SelectionBox",xy)
	yx.Adornee = xy
	yx.Color = BrickColor.new("Dark stone grey")
	
	M.Move:connect(function()
		if M.Target == game.Workspace.Base then
			--Now we need to find the x coordinates
			xValue = game.Workspace.Base.CFrame:toObjectSpace(M.Hit).X
			local xRoundValue = xValue%4
			if xRoundValue == 3 or xRoundValue == 2 then
				xValue = math.ceil(xValue/4)*4
			else
				xValue = math.floor(xValue/4)*4
			end
			
			--We also need to find our z coodinates
			zValue = game.Workspace.Base.CFrame:toObjectSpace(M.Hit).Z
			local zRoundValue = zValue%4
			if zRoundValue == 3 or zRoundValue == 2 then
				zValue = math.ceil(zValue/4)*4
			else
				zValue = math.floor(zValue/4)*4
			end
			
			--Now it is time to actually move the brick
			if checkAvaliablity(xValue,zValue) then
				xy.CFrame = game.Workspace.Base.CFrame:toWorldSpace(CFrame.new(xValue,2.5,zValue))--2.5 will never change as long as the base and brick is the same
			end
		end
	end)
	
	--This actually creates the brick
	M.Button1Down:connect(function()
		--Put the brick down
		local brk = Instance.new("Part", game.Workspace)
		brk.Size = Vector3.new(4,4,4)
		brk.Anchored = true
		brk.CFrame = xy.CFrame
		
		--Lock the space
		local x = math.floor((xValue + 30)/4)
		local z = math.floor((zValue + 30)/4)
		avaliableSpaces[x][z] = 1
		
		--Move the invisible brick away
		xy.CFrame = CFrame.new(0,0,0)
	end)
end)

--Destory the brick when the tool is unequipped
script.Parent.Unequipped:connect(function()
	game.Workspace:FindFirstChild(game.Players.LocalPlayer.Name.."Brick"):Destroy()
end)

It doesn't work for anything except one level above the base. It isn't stackable yet. Currently it decides if a space is open by checking a preset database at the top. I don't like this but I haven't found a way around it yet.

It moves in a 4x4 grid. The base is a 60x60 stud brick.

I am open to any suggestions.