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.
Dining tables and even casual eating tables are standard at 30 inches. Some older, vintage tables are 29 to 29 Â½ inches. I think 30 inches is best, even for tall people. Dining chair seat height is typically 17 to 19 inches. If you would like armchairs, make sure you check any apron details on the table to ensure the chairs fit comfortably under the table.