diff --git a/geometry.lua b/geometry.lua
new file mode 100644
index 000000000..157993b72
--- /dev/null
+++ b/geometry.lua
@@ -0,0 +1,227 @@
+--[[
+2D Geometry utilities
+
+all of these apply to full rectangles { x = ..., y = ..., w = ..., h = ... }
+
+some behaviour is defined for points { x = ..., y = ... }
+some behaviour is defined for dimensions { w = ..., h = ... }
+
+just use it on simple tables that have x, y and/or w, h
+or define your own types using this as a metatable
+]]--
+Geom = {
+	x = 0,
+	y = 0,
+	w = 0,
+	h = 0
+}
+
+function Geom:new(o)
+	local o = o or {}
+	setmetatable(o, self)
+	self.__index = self
+	return o
+end
+
+function Geom:copy(o)
+	local n = self:new()
+	n.x = o.x
+	n.y = o.y
+	n.w = o.w
+	n.h = o.h
+	return n
+end
+
+function Geom:__tostring()
+	return self.w.."x"..self.h.."+"..self.x.."+"..self.y
+end
+
+--[[
+offset rectangle or point by relative values
+]]--
+function Geom:offsetBy(dx, dy)
+	self.x = self.x + dx
+	self.y = self.y + dy
+end
+
+--[[
+offset rectangle or point to certain coordinates
+]]--
+function Geom:offsetTo(x, y)
+	self.x = x
+	self.y = y
+end
+
+--[[
+scale rectangle (grow to bottom and to the right) or dimension
+
+if a single factor is given, it is applied to both width and height
+]]--
+function Geom:scaleBy(zx, zy)
+	self.w = self.w * zx
+	self.h = self.h * (zy or zx)
+end
+
+--[[
+return the outer rectangle that contains both us and a given rectangle
+
+works for rectangles, dimensions and points
+]]--
+function Geom:combine(rect_b)
+	local combined = Geom:new(self)
+	if combined.x > rect_b.x then
+		combined.x = rect_b.x
+	end
+	if combined.y > rect_b.y then
+		combined.y = rect_b.y
+	end
+	if self.x + self.w > rect_b.x + rect_b.w then
+		combined.w = self.x + self.w - combined.x
+	else
+		combined.w = rect_b.x + rect_b.w - combined.x
+	end
+	if self.y + self.h > rect_b.y + rect_b.h then
+		combined.h = self.y + self.h - combined.y
+	else
+		combined.h = rect_b.y + rect_b.h - combined.y
+	end
+	return combined
+end
+
+--[[
+returns a rectangle for the part that we and a given rectangle share
+
+TODO: what happens if there is no rectangle shared? currently behaviour is undefined.
+]]--
+function Geom:intersect(rect_b)
+	local intersected = Geom:new(self)
+	if self.x < rect_b.x then
+		intersected.x = rect_b.x
+	end
+	if self.y < rect_b.y then
+		intersected.y = rect_b.y
+	end
+	if self.x + self.w < rect_b.x + rect_b.w then
+		intersected.w = self.x + self.w - intersected.x
+	else
+		intersected.w = rect_b.x + rect_b.w - intersected.x
+	end
+	if self.y + self.h < rect_b.y + rect_b.h then
+		intersected.h = self.y + self.h - intersected.y
+	else
+		intersected.h = rect_b.y + rect_b.h - intersected.y
+	end
+	return intersected
+end
+
+--[[
+set size of dimension or rectangle to size of given dimension/rectangle
+]]--
+function Geom:setSizeTo(rect_b)
+	if self.w == rect_b.w and self.h == rect_b.h then
+		return false
+	end
+	self.w = rect_b.w
+	self.h = rect_b.h
+	return true
+end
+
+--[[
+check whether rect_b is within current rectangle
+
+works for dimensions, too
+for points, it is basically an equality check
+]]--
+function Geom:contains(rect_b)
+	if self.x <= rect_b.x
+	and self.y <= rect_b.y
+	and self.x + self.w <= rect_b.x + rect_b.w
+	and self.y + self.h <= rect_b.y + rect_b.h
+	then
+		return true
+	end
+	return false
+end
+
+--[[
+check for equality
+
+works for rectangles, points, dimensions
+]]--
+function Geom:__eq(rect_b)
+	if self.x == rect_b.x
+	and self.y == rect_b.y
+	and self:equalSize(rect_b)
+	then
+		return true
+	end
+	return false
+end
+
+--[[
+check size of dimension/rectangle for equality
+]]--
+function Geom:equalSize(rect_b)
+	if self.w == rect_b.w
+	and self.h == rect_b.h
+	then
+		return true
+	end
+	return false
+end
+
+--[[
+check if our size is smaller than the size of the given dimension/rectangle
+]]--
+function Geom:__lt(rect_b)
+	debug("lt:",self,rect_b)
+	if self.w < rect_b.w and self.h < rect_b.h then
+debug("lt+")
+		return true
+	end
+debug("lt-")
+	return false
+end
+
+--[[
+check if our size is smaller or equal the size of the given dimension/rectangle
+]]--
+function Geom:__le(rect_b)
+	if self.w <= rect_b.w and self.h <= rect_b.h then
+		return true
+	end
+	return false
+end
+
+--[[
+offset the current rectangle by dx, dy while fitting it into the space
+of a given rectangle
+
+this can also be called with dx=0 and dy=0, which will fit the current
+rectangle into the given rectangle
+]]--
+function Geom:offsetWithin(rect_b, dx, dy)
+	-- check size constraints and shrink us when we're too big
+	if self.w > rect_b.w then
+		self.w = rect_b.w
+	end
+	if self.h > rect_b.h then
+		self.h = rect_b.h
+	end
+	-- offset
+	self.x = self.x + dx
+	self.y = self.y + dy
+	-- check offsets
+	if self.x < rect_b.x then
+		self.x = rect_b.x
+	end
+	if self.y < rect_b.y then
+		self.y = rect_b.y
+	end
+	if self.x + self.w > rect_b.x + rect_b.w then
+		self.x = rect_b.x + rect_b.w - self.w
+	end
+	if self.y + self.h > rect_b.y + rect_b.h then
+		self.y = rect_b.y + rect_b.h - self.h
+	end
+end