Made these for my In_laws 40th year anniversary Party.  We made about 75.  It took me all day to figure out how to design it on INKscape but it took us less than a day to finish them.   I didn't know we could reuse the etching cream.   On the front we etched a coyote howling at the moon and a cactus.  (Typical South Texas and the family has a ranch named "El Coyote Ranch".) On the opposite side we etched their initials with a western font.   Everyone in the family helped even my father-in-law.

Posit it note covers

Lolis my Friend made these for all her friends. Everyone at school loved them.  She used the pattern for the box from an svg file and cut it with the cricut.  They Look GREAT!

Masking Technique

You can make it two different way; one by drawing in the lines with a marker and the other by sponging without drawing the lines.
First, started with a square of white cardstock.  Then, make a pattern for the grids by cutting a second square into 3 random pieces.  A pattern is not necessary but if you are going to make several cards the same a pattern will help.  Then, trace the pattern pieces with a Sharpie marker to get the black lines.
Next, mask off each section, one at a time and stamped the images with black ink.  Once again, masked them each again, sponging them with 3 different colors of ink.  It really doesn’t matter if you stamp first or sponge first.  If you stamp first, then you have a little more control over where your lighter, highlighted areas are.
The second way to do this technique is to not draw in any lines.  If you choose to use this technique you must do your sponging first.  Then, mask off and sponge each section.   The  sections may overlap if you want.  Continue until you fill the cardstock.  Then come back and mask the sections again, this time stamping various coordinating images in each one.  By doing it this way, it is sometimes best to choose only 2 colors of ink that blend well together to avoid the sections looking “muddied” where they overlap.

Ink and Cuttlebug Folders

Use Cuttlebug folders to letterpress. Start by taking a Textile CB folder and inking the bottom inside plate with any color of your choice ink. Next, placed the cardstock inside the folder and ran it through the CB upside down (the Cuttlebug logo is on the bottom instead of the top). {Be sure to rinse your folder off with water immediately, so it doesn't stain.} Then, just cut the pieces to size and inked the edges with the same color of ink you have chosen. (upside down so it debosses). 
FYI: You want to make sure you stamp first, and that you deboss instead of emboss, or it will be hard to read your sentiment. Then you may color in the debossed image.