Photograph credits
- Rows of clay bricks and stacked clay bricks, by McKay Savage, CC BY 2.0, via Wikimedia Commons and Wikimedia Commons. Cropped and compressed.
- M-sand, by Thamizhpparithi Maari, CC BY-SA 4.0, via Wikimedia Commons. Compressed.
- Jelly stone close up, by irvin calicut, CC BY-SA 3.0, via Wikimedia Commons. Compressed.
- Jelly stone heap, by RanjithSiji, CC BY-SA 3.0, via Wikimedia Commons. Cropped and compressed.