Parametric version of bsutton's excellent bed level test object. Includes a greater number of test points spread evenly across the bed.
This object is designed to help you check that you are correctly leveling you printer bed. It prints nine super thin squares in each corner of you printer bed.
The objects should appear even with a smooth surface.
Level your bed, print the object and check the results.
You may want to download the scad file and adjust the x and y dimensions to match your printer bed.
The default values are:
X_MAX_LENGTH = 210;
Y_MAX_LENGTH = 178;
See the calibration page on reprap.org for full details on calibrating your printer.