This is based on the very real postcard we sent to special people in 2113; I have been making postcards like this since 2002. This quilt design came after EQ had a challenge on creating Serendipity blocks.
We use graphics software; an under $30 one works fine. I design the quilt and export a picture of it to the front outside. I then make a companion ‘quiltlet’ for the message and export that to the outside back. (If the quilt you design is non-directional, you can use the inside front and inside back.) I then print this on cardstock and cut the cardstock in half. Make sure the cardstock is turned so that the quilt prints on the reverse of the message.
Not shown: the Bible verse or hymn and credits for the message ‘quiltlet’ and notes that I designed the card and the year, flanking the quilt. This size requires a first-class stamp.