Modern Pillowcase Quilt Pattern

I want to publish a clear, beginner-friendly pattern for a modern quilted pillowcase (approx. 20" × 26"). The aesthetic I’m after is clean and contemporary, so think bold geometry and fresh color blocking rather than traditional motifs.

Here’s what I need from the finished file I can provide measurements and pictures

• An original block or all-over design scaled precisely to a single pillowcase.
• Yardage chart and exact cutting measurements that a first-time quilter can follow.
• Step-by-step piecing, pressing, and assembly instructions written in plain, encouraging language.
• Simple line illustrations or labeled diagrams (vector or 300 dpi PNG) showing every stage.
• Finishing options for either an envelope back or zipper closure, plus binding or top-stitch details.

Please deliver a print-ready PDF along with the editable source for the graphics. Accuracy within ⅛" on all measurements and proof-read US English are my acceptance checkpoints. If you can add a quick EQ8 or Illustrator mock-up of the final look, that’s a bonus but not mandatory.