The first panel on the left shows the MatchTool, our utility for Graphical Search and Replace. At the top are two search and replace panes (containing an oak and maple leaf in this example). The user specifies via a set of checkboxes which graphical properties are significant in the search and replace examples. This pattern was used to change the oak leaves to maple leaves in the pink panel below it.
Another way to create a maple tree is shown in the third panel. Initially we start with the search pattern on the left and replace a black line with a brown line and three black lines. This substitution is repeated until we have a brown tree with black lines instead of leaves. Finally we replace the black lines with leaves using the replacement pattern on the right. In effect, the tree was created using a graphical grammar.
The final three panels show other graphical grammars. In the first of these we create a triadic koch snowflake by starting with a triangle and repeatedly replacing all lines with set of 4 connected segments shown in the replace pane.
In the next panel we create a golden spiral by starting with a blue rectangle and repeatedly replacing blue rectangles of that shape (at any rotation and scale), with a blue square, white arc, and smaller blue rectangle as shown in the replace pane.
The final panel shows the "MatchTool Spiral", which we created by starting with a line, and repeatedly replacing it with the letters "MATCHTOOL" in a spiral arc, followed by another line. Since it would be difficult to position the letters in the Replace pane by hand, we used the MatchTool to actually create the Replace pane contents, in a manner we won't go into here.
Although the MatchTool is a fun and easy utility for creating shapes from graphical grammars, it is more frequently used to eliminate the drudgery of making repeated substitutions in a regular scene - as demonstrated in the first example where oak leaves were replaced by maple leaves.