In this video, a single-digit adder is implemented to demonstrate that numerical calculation can be done visually. This adder requires 29 shape rules which accomplish three different main operations: a) translating numbers (1, 2, 3, …, 9) to numbers of 1s (1, 11, 111, …, 111111111), b) moving all the 1s together and c) translating number of 1s (1, 11, 111, …, 111111111) to numbers (1, 2, 3, …, 9, 10). The concept of addition, moving all the 1s together, is commonly used in digital environment. Shape Machine can process this operation visually with a simple shape rule which is demonstrated in another video example (Sorting Binary) to achieve an adder. This example is a proof that implementing a computer with shape grammar is very possible in theory. This may lead us to another question: Can we implement a visual computer and how different will it be?