You can create your own symbol.
A symbol is defined by a series of lines linking points in a 50 by 50 matrix.
You can create a brand new symbol starting from an empty canvas by clicking twice to define extremities of each line. Once satisfied, enter a name in the field below the canvas and press Save.
Top of the screen, a popup menu with all the pre-defined symbols. You can load by pressing “Load” to modify it, or start a new drawing from it.
To delete any of the line, hover over it until it changes color. When color has changed, either press the Delete key on the keyboard, or right click.