It is drawn for 3D by using overlays over a background board.
Elder follows Al Feldstein’s original version of “The Strange Couple” in The Vault of Horror #14 (actual issue #3), from 1950.
I have an earlier posting (see the link below) to a posting showing Feldstein’s version, and the 3D story itself, plus a bonus from Boy’s Life, showing how to make your own 3D glasses.
FELDSTEIN EXPLAINS ABOUT WRITING “THE STRANGE COUPLE”
In an interview with Grant Geissman for the book, Tales of Terror!/The EC Companion by Geissman and Fred Von Bernewitz, Feldstein tells of writing “The Strange Couple” with Gaines, first as a class assignment for an adult course taught by writer Theodore Sturgeon.
Feldstein said, “[The story] was a straight original.”*
“There was an adult course in writing . . . we [Gaines and Feldstein] figured it would help us in writing, plotting and things like that. So we went to this course and [Sturgeon] was talking about how he writes, basics, blah-blah, and we were assigned to do a short story, and we asked if we could collaborate. He said ‘sure.’ We went back and we typed up in text form ‘The Strange Couple.’
“. . . Sturgeon went crazy; he loved it . . . that was kind of an ego thing, so we felt we didn’t need the goddamn course.”
*As opposed to many other EC stories which had their genesis in the works of other writers. — Pappy
This the link to the earlier post. Just click on the thumbnail.