Kmaps

3. Once you fill up the Kmap with the correct bits, it's time to encircle groups of $1$s according to the following principles:
   1. The groups must be of cells that contain only $1$s.
   2. The number of cells in the group must be a power of $2$, both vertically and horizontally. For example, valid groups are of the dimensions $1 \times 1$, $1 \times 2$, $2 \times 1$, $2 \times 2$, $1 \times 4$, $4 \times 1$, $4 \times 2$, etc. A group of the size $1 \times 3$, for example, isn't valid since $3$ is not a power of $2$.
   3. The groups must be built up of rows and columns: they can't be built through diagonals.
   4. The groups must be made as large as possible. For example, a row in a Kmap that contains four $1$s must be grouped as $4 \times 1$, not as two separate groups of $2 \times 1$.
   5. Each of the $1$s in the Kmap must belong to at least one group that you create: don't leave any $1$ without a group.
   6. Groups can overlap with one another. Also, groups can 'wrap-around' the corners of the Kmap.

Back to our example and Kmap on slide 53, we created two groups: the blue $1 \times 2$ group and the red $2 \times 1$ group.