Smartichoke's manual has information on how bonus and penalty petals work, but let's expand on it with some examples!
To recap, petals start at a normal shade and are worth 100 points. Petals also earn bonuses (green) and penalties (red), which also affect their point values:
Bonuses and penalties are all about connected letters! You can select letters from any petal, but connected letters help you earn bonuses and disconnected letters lead to penalties.
If a petal is adjacent to three or more connected letters, then it earns bonuses. If a petal is adjacent to one or more disconnected letters, then it earns penalties.
Now, let's take a look at some examples!
We'll highlight the word BRACE, with B and R disconnected and A-C-E connected:
Now, let's highlight the petals that are adjacent to the connected letters. You can tap the image to turn on/off highlights that show how each petal is connected:
Now, let's highlight the petals that are adjacent to the disconnected letters. Again, tap to toggle the highlights:
One of those petals overlaps. It's adjacent to two connected letters and one disconnected letter. So, one of each cancels out and you're left with a petal that's adjacent to one connected letter:
After you submit the word, notice that the petal with a negative ends up with a penalty. Tap to flip back to the highlighted word:
What's happening with all of those connected letters? Why aren't there any bonus petals? Remember that petals earn bonuses when they're adjacent to three or more connected letters. So, let's take a look at an example that does.
In this case, all of the letters in DOUSES are connected. (There's a break in the middle of the word, but each letter is still connected to another letter.)
Let's highlight all of the adjacent petals and their counts. Tap to toggle the highlights:
In this example, we have two petals that are going to receive a bonus. One petal (+3) will receive a single bonus and move one level up. The other, though, has +5, which means it's going to go up three bonus levels (the bonus from being adjacent to three petals, plus two more)!
Again, tap to flip back to the highlighted word: