diff --git a/exp/geometry.py b/exp/geometry.py
new file mode 100644
--- /dev/null
+++ b/exp/geometry.py
@@ -0,0 +1,55 @@
+import math
+
+import numpy as np
+
+from analyzer.epoint import EPoint, homogenize
+from analyzer.grid import transformPoint
+
+
+class Line():
+	def __init__(self,a,b):
+		self.a=a
+		self.b=b
+		self.points={a,b}
+
+	def getSortedPoints(self):
+		return tuple(sorted(self.points))
+
+	def computeAngle(self,line):
+		ab=self.a-self.b
+		cd=line.a-line.b
+		alpha=math.atan(ab.y/ab.x)
+		gamma=math.atan(cd.y/cd.x)
+		fi=max(alpha,gamma)-min(alpha,gamma)
+		return min(fi,math.pi-fi)
+
+	def intersect(self,line):
+		p=self.toProjective()
+		q=line.toProjective()
+		return EPoint.fromProjective(np.cross(p,q))
+
+	def toProjective(self):
+		return homogenize(np.cross(self.a.toProjective(),self.b.toProjective()))
+
+	def transform(self,matrix):
+		a=EPoint.fromProjective(transformPoint(self.a.toProjective(),matrix))
+		b=EPoint.fromProjective(transformPoint(self.b.toProjective(),matrix))
+		if a is None or b is None: return None
+		return Line(a,b)
+
+	def __str__(self): return "({0},{1})".format(self.a,self.b)
+	def __repr__(self): return "Line({0},{1})".format(repr(self.a),repr(self.b))
+
+
+def point2lineDistance(a,b,p):
+	# https://en.wikipedia.org/wiki/Point-line_distance#Line_defined_by_two_points
+	ab=b-a
+	num=abs(ab.y*p.x - ab.x*p.y + b.x*a.y - a.x*b.y)
+	denum=math.sqrt(ab.y**2+ab.x**2)
+	return num/denum # double_area / side_length == height
+
+
+def angleDiff(alpha,beta):
+	diff=abs(alpha-beta)
+	if diff>math.pi: diff=2*math.pi-diff
+	return diff