This instructable explains how to make a multi-coloured adhesive vinyl which can be viewed from the other side of glass (as opposed to the multi-layered aproach which is much faster and easier but can only be viewed from the same side which can be viewed here https://www.instructables.com/id/Multi-Coloured-Vinyl-Cutting/ )
Step 1: Overview and Materials
The technique involves cutting identical profiles from several coloured vinyl sheets, removing the parts you dont want, then lifting up one set of coloured cuts after another using clear adhesive sheet (e.g. tape)
The trick for lining it up is to tightly suspend the clear adhesive sheet with the first set of coloured vinyl pieces, above a backing board which holds the second set. This allows very precise and careful lining up before the second layer is picked up by the transparent adhesive.
You will need:
-Silhouette Portrait desktop vinyl cutter
-Computer running Silhouette Studio
-Vinyl (several smaller sheets of different colours)
-Sharp nosed tweezers
-Transparent adhesive sheet / tape
-A clean, dust free working area
-Spacers which are slightly thicker than the backing board (by approx 2mm)
Step 2: Cut and Prepare Profiles
Cut identical profiles onto each of the coloured vinyls
Use tweezers to remove the unwanted pieces, leaving only the requIred areas (the green features along the top in the image were removed before they were stacked up)
A piece of upturned tape can be used to gather the scraps from your tweezer tips.
Step 3: Pick Up First Set of Coloured Vinyl
Stick the clear adhesive sheet to the first set (of coloured adhesive sections)
Step 4: Align Second Set of Coloured Vinyl
Pull the adhesive sheet tightly (being careful not to stretch it at all) between the two spacers which are on a flat surface.
Stick the second set to the backing board.
Move the backing board around underneath the first set until you are happy they are lined up.
Gently press down on the transparent adhesive to bring it into contact with the second set and pick it up.
Step 5: Peel Off Wax Backing Paper
If the transparent adhesive does not pick up the new set easily, you may have to use the technique shown in the image. It involves placing the transparent adhesive face down on a flat surface and pull the backing up against a sharp corner (such as around the right-angled edge of a metal ruler) the abrupt bend will peel the waxed backing paper from both/ all sets adhesive vinyls, leaving you with the adhesive surfaces shown.
Step 6: Stick to the Surface and Peel Off Transparent Adhesive
Stick the whole thing to the window/ other, and peel the transparent adhesive off.
Pulling back at a sharp angle gives you the best chance at separating all of the vinyl pieces from the transparent adhesive (you can see the "a" is being lifted off. Stick it back on and pin it down with tweezers if neccesary)
Remember, be patient and pay attention to detail. If this is too tricky and time consuming, consider doing it using the simpler method. https://www.instructables.com/id/Multi-Coloured-Vinyl-Cutting/