anchor.diff:      ;;VBO yes, this is necessary, because it associates the vbo
       ;;with the vao
   
  -    ;;postion
  +    ;;position
       (gl:bind-buffer :array-buffer position-vbo)
       (%gl:enable-vertex-attrib-array 0)
       (%gl:vertex-attrib-pointer 0 3 :float :false 0 0)
  
positive.code: 
  (defun draw-lines ()
    ;; in mode :LINES DRAW-ARRAYS each COUNT takes 2 components, i.e. "2" would mean that it
    ;; will read _4_ components from the gpu array.  Because we defined one vertex having 3
    ;; components (gl:vertex-attrib-point...). We need _6_ to draw a single line.
    ;; Again COUNT taking 2 at the same time a (draw-arrays :lines 0 3) <- will fetch 6 components
    ;; That's why we do the strange (* (length ..) 0.5) halving multiplication
  
negative.code: (defun make-seq-hash-table ()
    (make-instance 'sequential-hash-table))
  
  ;; it looks like a hash-table, this might be counter-intuitive as GETHASH, CLRHASH etc. don't work
  (defmethod print-object ((s sequential-hash-table) stream)
    (declare (type stream stream))
    (let ((hash-table (the-table s)))
  