This is an easy project and it makes a nice accent piece to hang in the garden, on a wall in the house or in front of a window to catch the light. It needs no special skills and can be done very cheaply. The best thing is, folks will think you spent a fortune to buy it.
Step 1: Prepare the Window
First you have to find a window. These can be had for free if you know someone who replaces windows, but antique stores or your local Restore are good places to look. Make sure it has a wood frame and the glass is intact.
Re-finishing the frame is the next step. You could paint it, strip and stain it, or leave it natural which is basically what I did.
In order to give it a more rustic look, however, I chamfered all edges with a block plane to a rough 45 degree angle. Some of the putty on the non-show side was missing so I patched it with silicone caulking. Both sides were painted white and I used a drill with a wire wheel to abrade it so some wood would show through. Lastly I sanded it with #80 and gave all the wood two coats of outdoor semi- gloss clear varnish. I also installed two sturdy screw eyes to the top of the frame to make it easy to hang outside.
Step 2: Design and Paint Your Motif
I decided on a birch tree theme and after viewing many sketches online drew my own scale replica on paper. When happy with the result, and after cleaning the glass surfaces thoroughly, I used a fine washable marker to reproduce the design on the front glass surfaces. Next, I turned the window over and painted the design on the reverse side following the markered lines. Since I used only black and white, this was simple, but I had to paint the black on first and after it was dry, followed up with the base colour, white.. The reverse of what you would think. You have to use glass paint which is readily available in your local craft store. If you are not a good artist, it is possible to copy a picture you like but my best advice is to keep it simple. When it dries, you can wash off the marker and hang it up.