diff --git a/content/geometry/SegmentDistance.h b/content/geometry/SegmentDistance.h
index fa6624787..c966365c9 100644
--- a/content/geometry/SegmentDistance.h
+++ b/content/geometry/SegmentDistance.h
@@ -21,7 +21,7 @@ Returns the shortest distance between point p and the line segment from point s
 #include "Point.h"
 
 typedef Point<double> P;
-double segDist(P& s, P& e, P& p) {
+double segDist(P s, P e, P p) {
 	if (s==e) return (p-s).dist();
 	auto d = (e-s).dist2(), t = min(d,max(.0,(p-s).dot(e-s)));
 	return ((p-s)*d-(e-s)*t).dist()/d;
diff --git a/content/geometry/circumcircle.h b/content/geometry/circumcircle.h
index e45f402a8..bec03ebc5 100644
--- a/content/geometry/circumcircle.h
+++ b/content/geometry/circumcircle.h
@@ -18,11 +18,11 @@ The circumcirle of a triangle is the circle intersecting all three vertices. ccR
 #include "Point.h"
 
 typedef Point<double> P;
-double ccRadius(const P& A, const P& B, const P& C) {
+double ccRadius(P A, P B, P C) {
 	return (B-A).dist()*(C-B).dist()*(A-C).dist()/
 			abs((B-A).cross(C-A))/2;
 }
-P ccCenter(const P& A, const P& B, const P& C) {
+P ccCenter(P A, P B, P C) {
 	P b = C-A, c = B-A;
 	return A + (b*c.dist2()-c*b.dist2()).perp()/b.cross(c)/2;
 }
diff --git a/content/geometry/kdTree.h b/content/geometry/kdTree.h
index 4c32621d6..a456f4650 100644
--- a/content/geometry/kdTree.h
+++ b/content/geometry/kdTree.h
@@ -13,15 +13,15 @@ typedef long long T;
 typedef Point<T> P;
 const T INF = numeric_limits<T>::max();
 
-bool on_x(const P& a, const P& b) { return a.x < b.x; }
-bool on_y(const P& a, const P& b) { return a.y < b.y; }
+bool on_x(P a, P b) { return a.x < b.x; }
+bool on_y(P a, P b) { return a.y < b.y; }
 
 struct Node {
 	P pt; // if this is a leaf, the single point in it
 	T x0 = INF, x1 = -INF, y0 = INF, y1 = -INF; // bounds
 	Node *first = 0, *second = 0;
 
-	T distance(const P& p) { // min squared distance to a point
+	T distance(P p) { // min squared distance to a point
 		T x = (p.x < x0 ? x0 : p.x > x1 ? x1 : p.x);
 		T y = (p.y < y0 ? y0 : p.y > y1 ? y1 : p.y);
 		return (P(x,y) - p).dist2();
@@ -48,7 +48,7 @@ struct KDTree {
 	Node* root;
 	KDTree(const vector<P>& vp) : root(new Node({all(vp)})) {}
 
-	pair<T, P> search(Node *node, const P& p) {
+	pair<T, P> search(Node *node, P p) {
 		if (!node->first) {
 			// uncomment if we should not find the point itself:
 			// if (p == node->pt) return {INF, P()};
@@ -68,7 +68,7 @@ struct KDTree {
 
 	// find nearest point to a point, and its squared distance
 	// (requires an arbitrary operator< for Point)
-	pair<T, P> nearest(const P& p) {
+	pair<T, P> nearest(P p) {
 		return search(root, p);
 	}
 };
diff --git a/content/geometry/lineDistance.h b/content/geometry/lineDistance.h
index 377a09565..d672375e9 100644
--- a/content/geometry/lineDistance.h
+++ b/content/geometry/lineDistance.h
@@ -21,6 +21,6 @@ Using Point3D will always give a non-negative distance. For Point3D, call .dist
 #include "Point.h"
 
 template<class P>
-double lineDist(const P& a, const P& b, const P& p) {
+double lineDist(P a, P b, P p) {
 	return (double)(b-a).cross(p-a)/(b-a).dist();
 }
diff --git a/content/geometry/linearTransformation.h b/content/geometry/linearTransformation.h
index 74f175d8c..1f83b1882 100644
--- a/content/geometry/linearTransformation.h
+++ b/content/geometry/linearTransformation.h
@@ -19,8 +19,7 @@
 #include "Point.h"
 
 typedef Point<double> P;
-P linearTransformation(const P& p0, const P& p1,
-		const P& q0, const P& q1, const P& r) {
+P linearTransformation(P p0, P p1, P q0, P q1, P r) {
 	P dp = p1-p0, dq = q1-q0, num(dp.cross(dq), dp.dot(dq));
 	return q0 + P((r-p0).cross(num), (r-p0).dot(num))/dp.dist2();
 }
diff --git a/content/geometry/sideOf.h b/content/geometry/sideOf.h
index e84fcdc7e..14e31ae78 100644
--- a/content/geometry/sideOf.h
+++ b/content/geometry/sideOf.h
@@ -19,7 +19,7 @@ template<class P>
 int sideOf(P s, P e, P p) { return sgn(s.cross(e, p)); }
 
 template<class P>
-int sideOf(const P& s, const P& e, const P& p, double eps) {
+int sideOf(P s, P e, P p, double eps) {
 	auto a = (e-s).cross(p-s);
 	double l = (e-s).dist()*eps;
 	return (a > l) - (a < -l);