Parthoscreen

Monospaced Mode

Only monospaced mode is supported by the Parthoscreen. All characters in a given panel are the same size, and adjacent cells in a given panel may be merged to form a subpanel. Panels and subpanels can contain a widget, graphic, or a block of text. Different panels containing text need not share the same font size. Subscripts and superscripts are offset vertically by half the height of a character cell. Lines of text can optionally be separated by a gap equal to half of a character cell. The canvas property of a panel supports drawing graphics such as lines, circles, and rectangles. Panels with canvases do not contain a character grid.

Split Screen

The top half of the Parthoscreen is used by the tutor, and the bottom half of the screen is used by the learner. Both users can highlight/copy text on the other user's halfscreen and paste it on their own screen. Both halfscreens can scroll vertically, so they can contain dozens of lines if needed. Chat window: always on top, yellow background, variable width font. Audio is provided by cellphones on speaker phone. Only monospaced mode is supported: all characters within a given panel are the same size.

Math Commands

• Use the arrow keys to move the cursor.
• Type underscore(s) to underline the numerator of a fraction.
• Use the special character command (Ctrl+K) to insert special characters such as pi, square root, sum, and integral.
• Use Ctrl+Tab/Shift+Tab to display/undo the next step in the math problem being solved.
• Type question mark (?) to explain the current step or to break the current step down into lower-level steps.
• Click on Help after typing question mark to access the help system.

Miscellaneous Commands

• Use asterisk and slash for multiply and divide.
• Fractions or matrices enclosed in brackets use tall brackets.
• Mixed numbers (example: three and a half) employ a vertical offset of half a character cell for the whole number.
• Smart down/up arrow: press it after inserting a character moves the cursor beneath/above that character.
• Functions such as lines and parabolas can be plotted interactively on a graph.
• The default-to-upper-case setting assumes that all letters entered are upper case (use the shift key to enter a lower case letter), so Caps Lock is redundant.

Expression Language

Mathematical expressions are encoded (internally) using a Parthonyte-style expression. Each step in the math problem being solved manipulates this expression. Even if the user enters steps in a different order than the default ordering, the simplification logic can handle that. The user can type Ctrl+Tab/Shift+Tab to redo/undo her previous step, as well as to redo/undo the computer's previous step.

Superscripts

Superscripts and subscripts are handled by employing a vertical offset of half a line per level of superscripting or subscripting. The caret symbol (^) is used as a superscript prefix, double-caret (^^) is used as a subscript prefix, and backslash (\) is used as an escape character (terminate super/subscript with a semicolon). Carets and double-carets cannot be mixed (exception: one level of superscript can be combined with one level of subscript).

Advanced Parthoscreen Commands

These next 2 paragraphs may be ignored (they are written in computerese). Use Shift+Arrow Key to highlight a rectangular block. Press Insert to insert a row or column of spaces before a highlighted block (insert blank line if no highlight). Press Shift+Insert/Delete to insert/delete an entire row/column when a block is highlighted. The next paragraph discusses commands handling multiple indent levels.

Press Enter at end of a line of text: insert blank line, back up on that line to line up with beginning of text on previous line. Press Enter on blank line to back up to line up with beginning of text on a previous line, or insert blank line if already at beginning of line. Press Tab to move forward to line up with beginning of first or next word on a previous line. Press Home to move to beginning of text on current line, press it again to toggle between beginning of line and beginning of text. The user doesn't have to memorize these commands: type question mark at any time to access the help system.