Perpetual calendar

A perpetual calendar comprising:

• a front panel permanently displaying a month grid of cells and weekday labels, the front panel selectively displaying preprinted numbers in the month grid of cells in an accurate configuration and number of days for any month;
• and
• an at least semi-transparent sheet coupled to and in front of the front panel and having a write-on/wipe-off surface,
• wherein the month grid of cells has a plurality of upper rows and at least one lower row, and the at least one surface further comprises:
• a first surface having a first number matrix displayed thereon, the first surface horizontally movable behind the plurality of upper rows;
• and
• a second surface having a second number matrix displayed thereon, the second surface horizontally movable behind the at least one lower row,
• wherein the first number matrix is arranged such that by moving the first surface horizontally in relation to the front panel, a plurality of numbers of the first number matrix are visible through the windows in the upper rows to accurately represent sequential dates of the upper rows of a calendar for a month starting on any weekday, and
• wherein the second number matrix is arranged such that by moving the second surface horizontally in relation to the front panel, a portion of the second surface is visible through at least one window of the at least one lower row, to accurately represent sequential dates for the at least one lower row of a calendar numbered for a month beginning on any weekday and having an accurate number of days for any month.

A perpetual monthly calendar comprising:

• a front panel having a grid of cells representing a month displayed thereon, each cell having a window, and the grid having seven columns representing weekdays, a plurality of upper rows representing upper rows of a monthly calendar and at least one lower row representing at least one lower row of a monthly calendar;
• a first surface having a first number matrix displayed thereon, the first surface coupled to the front panel and horizontally movable behind the plurality of upper rows;
• and
• a second surface having a second number matrix displayed thereon, the second surface coupled to the front panel and horizontally movable behind the at least one lower row;
• wherein the first number matrix is arranged such that by moving the first surface horizontally in relation to the front panel, a plurality of numbers of the first number matrix are visible through the plurality of windows in the upper rows, and can accurately represent sequential dates of the upper rows of a calendar for a month starting on any weekday, and
• wherein the second number matrix is arranged such that by moving the second surface horizontally in relation to the front panel, portion of the second surface is visible through at least one window of the at least one lower row, and can accurately represent sequential dates for the at least one lower row of a calendar numbered for a month beginning on any weekday and an accurate number of days for any month.