When you run the program you can enter numbers for the various patterns you have to draw. The right window will draw what your pattern is supposed to look like $($i$.$e$.,$ the expected patterns$),$ while the left window will be blank except the first pattern $($i$.$e$.,$ Pattern $1).$

In GeneratePattern.java, you will find that the shape of Pattern $1$ is controlled by the following nested loop structure in the first block of the switch statement in populateBoard:

switch $($patternNumber$)\{$

case $1$:

for $($int row $=0$; row $<$ MAXROW; row$++)$

for $($int col $=0$; col $<$ MAXCOL; col$++)$

board$[$row$][$col$]=$ num$++$;

break;