add issequence function to data and plot functions and examples for geometry

examples/geometry_hexahedra.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""Example geometry of hexahedra.
+
+:Date: 2019-12-24
+
+.. module:: geometry_hexahedra
+  :platform: *nix, Windows
+  :synopsis: Example geometry of hexahedra.
+
+.. moduleauthor:: Daniel Weschke <daniel.weschke@directbox.de>
+"""
+from pylib.geometry import World, Hexahedron
+from pylib.geometry_plot_pylab import cad_wireframe
+
+def geometry():
+  w = World()
+  for i in range(3):
+    for j in range(3):
+      for k in range(3):
+        w.add(Hexahedron().scale(0.8).translate(-2+2*i, -2+2*j, -2+2*k))
+  return w
+
+
+if __name__ == "__main__":
+  w = geometry()
+  #print(w.bounding_box())
+  #print(*w)
+  #print(w.wireframes_xyz())
+  cad_wireframe(w)