Filament Sample Palette

I'm not good at associating colors without actual samples. 
There is a lot of color palette around, but none meeting my requirements : simple (only one model), small and with the ability to compare the bottom and top surface finish, with or without ironing.

The top face is divided in two, half is ironed, half is not (white sample on the main picture). 
The bottom is… the bottom (green sample, rough because of my PEI plate). 

Here is the version 0, with a simple support for samples.
FreeCAD file is included.

Fab 

advices

Obviously, first find the right setup for the filament! (you may remark on the picture that I don't always follow my own advice :-)

Don't print the sample just after having changed the spool, or some residue of the previous color will corrupt your sample.

Settings

There is only one important setting : activate ironing, and only for the upper surface
The trick here is that half of the upper surface is one layer higher, and only this half should be ironed.

Note the dimension of sample are multiple of the usual default layer of .3 mm I don't know if it works for other layer height.