The Shifting Frame
An artist stands before a massive, crumbling ceiling mural. It is too big to see the whole picture while painting a single eyelash. To start, she holds a small wooden frame against the wall. She decides to focus only on the little patch visible inside that window.
She paints strictly inside the square. It is fast work, but a problem appears when she moves the frame. The lines do not match up at the edges. A tree branch in one square misses the trunk in the next, leaving a grid of disconnected blocks.
She tries a new trick. Instead of moving to the next empty spot, she shifts her frame just halfway over. Now it sits right on the seam where two squares met. This overlapping view lets her see the broken edges and knit the lines back together.
As she repeats this shifting process, small patches merge into larger shapes. She stops worrying about single brushstrokes and starts managing whole forms. Leaves turn into branches, and branches become trees. The system builds a big picture from simple details.
The artist steps down to look at the ceiling. It is no longer a patchwork quilt but a single, continuous image. By focusing on small spots but constantly shifting her view to bridge the gaps, she captured the massive painting without needing to see it all at once.