diff --git a/geometry/quad.cpp b/geometry/quad.cpp
index 0bb3295..ac6738c 100644
--- a/geometry/quad.cpp
+++ b/geometry/quad.cpp
@@ -27,6 +27,15 @@ Quad Quad::insetNESW(float offset) const {
 	return insetNESW(offset, offset, offset, offset);
 }
 
+Quad Quad::insetOpp(Cardinal side, float offset) const {
+    Quad q = (*this) << int(side);
+    Quad qb = (*this) << int(side);
+
+    qb = qb.inset(N,offset);
+    return Quad(q[NE],qb[NE],qb[NW],q[NW]);
+
+}
+
 Quad Quad::makeParallelogram() const {
     float l1, l2;
     Quad q(c[NE],c[SE],c[SW],c[NW]);
diff --git a/geometry/quad.hh b/geometry/quad.hh
index 043c6d6..3a1274c 100644
--- a/geometry/quad.hh
+++ b/geometry/quad.hh
@@ -27,6 +27,7 @@ class Quad {
 	Quad inset(Cardinal side, float offset) const;
 	Quad insetNESW(float offsetN, float offsetE, float offsetS, float offsetW) const;
 	Quad insetNESW(float offset) const;
+	Quad insetOpp(Cardinal side, float offset) const;
 	float length(Cardinal side) const;
 	float minLengthNS() const;
 	float minLengthEW() const;
diff --git a/rules/batiment/batimentquadblock.cpp b/rules/batiment/batimentquadblock.cpp
index 50dc3a9..2339965 100644
--- a/rules/batiment/batimentquadblock.cpp
+++ b/rules/batiment/batimentquadblock.cpp
@@ -10,21 +10,10 @@ void BatimentQuadBlock::getBoundingBoxPoints() {
 }
 
 bool BatimentQuadBlock::split() {
-    Quad me = c;
-    Quad ms = c;
-    Quad mw = c;
-    Quad mn = c;
-
-    me[NW] = me[NE] + ((me[NW] - me[NE]) / me.length(N))*28;
-    me[SW] = me[SE] + ((me[SW] - me[SE]) / me.length(S))*28;
-    mw[NE] = mw[NW] + ((mw[NE] - mw[NW]) / mw.length(N))*28;
-    mw[SE] = mw[SW] + ((mw[SE] - mw[SW]) / mw.length(S))*28;
-    mn.inset(W,-28); mn.inset(E,-28);
-    mn[SW] = mn[NW] + ((mn[SW] - mn[NW]) / mn.length(W))*28;
-    mn[SE] = mn[NE] + ((mn[SE] - mn[NE]) / mn.length(E))*28;
-    ms.inset(W,-28); ms.inset(E,-28);
-    ms[NW] = ms[SW] + ((ms[NW] - ms[SW]) / ms.length(W))*28;
-    ms[NE] = ms[SE] + ((ms[NE] - ms[SE]) / ms.length(E))*28;
+    Quad me = c.insetOpp(E,28);
+    Quad ms = c.inset(E,-28).inset(W,-28).insetOpp(S,28);
+    Quad mw = c.insetOpp(W,28);
+    Quad mn = c.inset(E,-28).inset(W,-28).insetOpp(N,28);
 
     addChild(new BatimentQuadMur(me,height));
     addChild(new BatimentQuadMur(mw,height));