How to check if parts are same colour?

The BrickColor property is a BrickColor referencing the color of the part. They can be compared using ==. If we had 4 parts, A, B, C, and D, then we would compare their colors like this:

if A.BrickColor == B.BrickColor
	and A.BrickColor == C.BrickColor
	and A.BrickColor == D.BrickColor
	then
	-- Do whatever conditionally
end

(Other comparisons like AB, BC, C~D also works)

This isn't a very elegant solution, though. If you wanted a more robust solution, we would probably define this as a function:

function sameColor(A,B)
	return A.BrickColor == B.BrickColor;
end

if sameColor(A,B) and sameColor(A,C)
	and sameColor(A,D) then
	-- Do whatever conditionally
end

We could do even better by allowing sameColor to take a list of parts as a parameter:

function sameColor(A,B)
	if not B then
		local allSoFar = true;
		for _,part in ipairs(A) do
			allSoFar = allSoFar and sameColor(A[1],part);
		end
		return allSoFar;
	end
	return A.BrickColor == B.BrickColor;
end

if sameColor({A,B,C,D}) then
	-- Do whatever conditionally
end

We could also use Lua's n-ary functions to make this more elegant:

function sameColor(A,...)
	local allSoFarSame = true;
	local t = {...};
	for i = 1,#t do
		allSoFarSame = allSoFarSame and (A.BrickColor == t[i].BrickColor);
	end
	return allSoFarSame;
end

if sameColor(A,B,C,D) then
	-- Do whatever conditionally
end