anchor.diff:      (defvar *y-scale* .5)
       (defvar *x-offset* 400)
       (defvar *y-offset* 400)
  +    (defvar *width* 800)
  +    (defvar *height* 500)
       (defvar *player* (create coords []
                                zone ""
                                zone-name ""
  
positive.code:     (defun draw-line (sx sy dx dy)
        "Draw a line given source/destination"
        (setf (@ *ctx* stroke-style) "#000000")
        (chain *ctx* (begin-path))
        (chain *ctx* (move-to sx sy))
        (chain *ctx* (line-to dx dy))
  
negative.code:             (chain *ctx* (translate sx sy))
              (chain *ctx* (begin-path))
              (chain *ctx* (move-to 0 0))
              (setf (@ *ctx* line-width) (/ 1 *x-scale*))
              (with-slots (direction) *player*
                (cond ((eq "North" direction) (chain *ctx* (line-to 0 (- sy dirlen))))
                      ((eq "South" direction) (chain *ctx* (line-to 0 (+ sy dirlen))))
  