Basic corner cases

From Petal Crashers Wiki

The same-distance priority rules for which direction a petal will move when pushed from multiple sides lead to a set of eight basic corner cases that players should keep in mind when evaluating whether or not a link will work correctly. Because the corner cases resolve by giving priority to right, then up/down, then left, the rule of thumb is that chains will work more often when they are going to the right, and less often when they are going to the left. The priority order does not apply if the two bursting petals are different distances from the petals which caused their groups to burst to begin with.

The eight situations

Corner cases of two different directions have four possible combinations of directions, and eight possible structures. Of these, four structures will form a functioning chain. If we consider chains starting from the middle of an L-shaped 3-petal group, the working structures are:

Right/up Right/down Up/left Down/left
rbb
rr
yy
ygg
p
pr
rr
bb
yb
y

And the non-working structures are:

Up/right Down/right Left/up Left/down
b
rb
rr
yy
yg
g
ppr
rr
bb
yyb