Morse code is commonly depicted as a series of dot or dash shapes. When used in puzzles it may also be seen as thematic long and short objects.
Reverse Lookup (Card Back)
To use, start at the top of the tree. Taking the symbols one at a time in order do the following. For each DASH, follow the left branch (solid line), and for each DOT, follow the right branch (dotted line). When you run out of symbols, the letter you're on is the decoded morse letter. If you have 5 dots or dashes, use the numbers reference to the left of the card instead.