You can use ^ and %, but must enter them in the _Alphanumeric variable twice as ^^ or %%. However, if you want to use the result (_RndAlphaNum) later in the batch file (other than Echoing to the screen), they might require special handling. You can even use a space, as long as it's not the last character in the string.
23 inches (59cm) is the minimum distance required for a chair behind a desk. This would fit a modest sized chair. For more comfort and to accommodate a bigger office chair increase the chair clearance to 30 inches (76cm). Office Chair tips. Swivel chairs make it easier to get in and out from behind your desk, especially if the space is a bit tight.
Then you can use this table to get more people together for a meal. Dining tables tend to be made to a standard height of 30 inches (76cm). When you're choosing a table or chairs, always remember to think about how the chairs work with the table. Dining chair seat height is usually 18 (46cm) high. Some tables have a kind of fringe under the table surface which strengthens the table but decreases the distance between knees and an obstruction.