3D Printer Calibration

I created this thing instead the standard 20x20 calibration cube, in order to:
- detect and calibrate axis scaling issue (like the 20x20 boxe)
- detect and calibrate axis offset issue (it's why I created10x10 and 20x20 boxes together)
- By the way I was able to correct the cooling: parameters and adding a custom cooling tube.
- The small 6mm cylinder, surface and letters quality can help to tune the Extruder flow.

After some adjustments, like shown on picture : the "AFTER" printed quality was realy better than the "BEFORE" one ... however the "AFTER" was printed at 0.2mm layer vs 0.1mm for the firstone...

I received my ANET A8 last week ... I'm now ready to print (accuratelly) usefull Things !