Myself Materiom https://materiom.org/recipe/47
This is a developed recipe from the cornstarch, which creates an unbreakable steady concrete structure. (Ingredients: 128g Baking Soda, 64g Cornflour, 8g Zelatyna, 12g gelatine, 45g flour, 110g water and optionally crushed beetroot skin.
Measure out all ingredients into separate bowls.
Put baking soda, cornflour, zelatyna (and optional beetroot) into a saucepan on high heated hob.
Add 98g of the water, then add gelatine.
Mix continuously. When you stop mixing you want to see the mixture bubble and expand.
Gently fold in half of the flour to thicken mixture and it will become a very dry mashed potato consistency.
Add the rest of the water, until it becomes very smooth and runny. Fold in the rest of the flour and turn the hob to a medium heat.
Wait for the mixture to become dough-like.
Allow the material dough to cool before rolling and shaping, then cast it into shapes.
Allow the forms to air dry for 1-2 days.