The hammer rang once. A spark jumped off the anvil and did not go out. It waited. They followed.

Beto was hanging washing on the line behind the mending shed. He squeezed a wooden peg. Its jaws opened. He let go on a sock. Its jaws shut.

"Two shapes," said Beto. "Open and shut. Same peg."

"How do we know it's the same peg?" asked Danya, just to be annoying. Beto threw a sock at him.

The spark slipped through the museum's back door into the workroom where the Sketcher and the Photographer work. They followed.

Margit had a page of letters for a new chain.

"This part I'd bet on," she said, and inked two thick halves. She drew them close together, shut like a closed book.

Where the halves joined, her pen stopped. She switched to pencil and drew the join faintly.

"Ink where I'm sure, pencil where I'm not," said Margit. "I'm sure of the two halves. I'm not sure how they sit."

Kemi came out of the cold room. This time she carried two pictures.

"I took it in the cold," she said. "Twice."

In the first photograph, the two halves were wide apart, like an open mouth.

In the second, the halves were shut tight. Between them sat a small round partner, held like a ball in a fist.

"Same protein," said Kemi. "Monday, with nothing nearby. Thursday, with the partner in the water."

Danya looked from one to the other. "They can't both be right," he said. "One of them must be a mistake. Throw it out."

"My photograph shows what was there, not why," said Kemi. "Both were there. On different days, with different things in the water."

"So they're both true?" asked Danya.

"A blur tells you something too," said Kemi. "So do two pictures that don't match. They tell you it moves."

Danya thought about that. He did not like two answers. But two real pictures were two real pictures.

"What was different on Thursday?" he asked.

"The partner," said Kemi. "On Monday there was nothing in the water but the protein. On Thursday I added the small round partner first. Then I froze it."

"So the partner changes the shape," said Danya. "Or the shape changes when the partner comes."

"That's a good question," said Kemi. "Which comes first? That one even scientists argue about."

Beto squeezed the peg again, slowly. Open. Shut.

"It's the join," he said. "The join is an elbow. The halves don't change. The elbow lets them swing."

He held Margit's drawing up to the light. The pencil was exactly at the elbow.

"So you weren't sure about the one bit that bends," said Beto.

"Show me the photograph," said Margit. She looked at both, side by side. "I want to be wrong if I'm wrong. My drawing is the shut one. I only drew one shape, because the letters gave me one."

"And the partner closes it," said Kemi. "When the partner arrives, the two halves swing shut around it."

Danya counted. Two real shapes. One drawn. One shape the drawing could not show.

They pinned the fifth pair to the board. This time it was one drawing on the left and two photographs on the right, open and shut.

The spark slipped back out through the museum door, and the workroom was dark again.

Back on the Green

The spark dimmed to a warm dot and settled back on the anvil. The Green was just the Green again.

Beto oiled the hinge of the shed door. Before, it stuck halfway. Now it swung all the way open and all the way shut, the same door in two shapes.