t1.x   Empty file. 
       Various ways to specify a float (database unit).
t2.x   Cells. 
       Various ways to specify cell names (id, string) and refer to them.
t3.x   Texts.
       Various ways to specify text strings and to refer to them.
t4.x   Rectangles
t5.x   Polygons
t6.x   Paths
t7.x   Trapezoids
t8.x   Placements
t9.x   Ctrapezoids
t10.x  Modal variables
t11.x  Properties
t12.x  Circles
t13.x  Layer names
t14.x  CBLOCK compression
t15.x  Strict mode