A waffle chart is a data visualization technique that displays progress towards a goal or the composition of a whole using a grid of small, equally-sized squares or rectangles. Each square or rectangle represents a value or a percentage of the total. The squares are often colored to indicate different categories or levels of performance. Waffle charts are similar to pie charts or treemaps, but they use a grid layout instead of circular or hierarchical layouts. Waffle charts can be used in a variety of contexts, such as tracking sales, visualizing survey results, or displaying demographic data.
Unlike creating other charts, to create a waffle chart, we first need to create a table in excel as examples below. The table should have 10 rows and 10 columns, representing a 10 x 10 grid of squares or rectangles. This data structure will enable us to plot the waffle chart in tableau. 
Then, Import the excel file into tableau. Bring Rows and columns from measures to dimensions, and change mark to square.
After that, for each grid, we need to assign an index to enable a comparison with our percentage.
Next, we need to calculate how much our customer segment has contributed to the overall sales, which can be calculated using the formula below.
Now, it is time to compare whether the index is greater than our previously calculated percentage and assign them two distinct colors. Drag the final Boolean field onto the Color shelf and change the table calculation to “computed by using Table (across then down)”. With these steps, you should have your final simple Waffle Chart!