| The Cellular Automata of John von Neumann
The Cut & Paste mode
This mode alternates with Draw & Run mode. To pass from Draw & Run mode to Cut & Paste mode, click button (Select) or choose the item Select in menu Edit.
Many buttons that appear enabled in the Draw & Run mode, as well as the possibility of changing the transition rules, are disabled in Cut & Paste mode. The Edit operations Cut, Copy, Paste, Drop, Flip, Rotate, which you can activate by clicking specific top-toolbar buttons or by choosing corresponding items of menu Edit, are instead enabled. These operations simplify greatly the construction of complicated automata.
In this mode, you can select any subset (fragment) of the current cell lattice by performing suitable sequences of rectangular selections (composite selections) and Edit operations. Fragments can be saved to or loaded from files with default extensions *.jfr (for JVN automata) or *.efr (for EVN automata). Moreover, in Cut & Paste mode, you can generate various sorts of tapes coding for selected rectangular areas to be attached to a constructor or a universal constructor.
You can perform composite selections and Edit operations by suitable clicking and dragging operations in the Synoptic View window as well. Button (Synoptic view window) toggles between showing and hiding this window. All the above-mentioned operations are simultaneously visible in both the Synoptic View and the Main View windows.
You can load a fragment from a fragment file by clicking button (Import fragment), or by selecting the item Import fragment in menu File. This button, as well as the corresponding menu item, is always enabled both in Cut & Paste mode and in Draw & Run mode. In contrast, button (Export fragment), as well as the item Export fragment in menu File, is used to save selected fragments to files with extensions *.jfr (JVN automata) or *.efr (EVN automata). The latter button is enabled only in Cut & Paste mode if Cut or Copy operations are not in use.
If a fragment is loaded when the program environment is set for Draw & Run mode, the environment passes automatically to Cut & Paste mode, where you can immediately perform the operations Drop, Flip, Rotate etc. Of course, to run a cell assembly loaded from a fragment file, you must pass from the Cut & Paste mode to the Draw & Run mode by clicking button (Deselect). You can generate tapes for specific constructors (single-tape JVN and EVN automata and 9-fold-tape EVN constructors) just after performing the first rectangular selection.
Note: After cutting or copying a fragment F, you can replace the current automaton with another one (governed by the same same transition rules) by loading the latter automaton from a file (with extension *.jvn or *.evn), and then pasting F into the new cell assembly. In this way, you can transfer any portion of a given automaton to any place of another automaton.