The Pegorans were an ancient culture of note, with a fascination for the "other worldly" and an emphasis on the symbolic, they have left their marks upon the world in the areas or architecture, math, and calligraphy.
Pegoran doors are special symbolic doors used in tombs, holy places, and places of the hearth. They are found in ancient buildings (when they were all the craze), places with pretense of being stately, artisitic, or "eternal" (like the City Folk of Artimas), or tombs.
Pegoran doors are circular doors made of stone (except when used in houses - which are wood). The door range from a hand span to finger span thick. Thicker doors have been found when used as "main entrances" or "security doors". While they can be plain, most proper doors have a bas relief of an intricate interwoven geometric pattern. The pattern is based upon the symbolic need/ purpose of the space the door is a guardian of, the location/ facing of the door, and the era of the door (styles change over time). The patterns weave, intermingle, and point, in a hauntingly beautiful way (think proper celtic knot work). Some modern copies incorporate heraldic or state devices into said pattern.
Some collectors use these doors as "art", either as free standing statuary or inset into a wall. The Prince of Artimas is known to pay many gold dragns (gold coins) for doors in good condition.
The door appears to be an circular indention in the walls. This door is set in a channel and rolls into wall to the right. That wall is usually thick with a carved out area for the door. When the door is rolled out, it leaves a circular passage to pass through.
While doors can be rolled by hand, most are moved by clever lever work. Simply touching the door or a point on the right side of the wall, will cause the door to roll. Since many "frames" are intricately carved, it can sometimes be a challange to find the "right place" to press. And since interesting prick traps can also be intergrated into the artwork, those who do not know the proper place to open the door can be quickly poisoned.
Some doors will close automatically after a certain amount of time will pass, others have to be actively closed (finding the corresponding "right spot" on the other side).
Note: Most "old doors" have a basic enchantment woven into the pattern. This prevents them from being opened by most knock or unlocking spells. Some will even resist magical liftings.
The problem with Pegoran doors is that they can be "tricky".
*Some Doors have activation mechanisms that are multipart. So there may be a "right place" or knob that may need to be switched down the hall or in another room entirely. So for an entrance to a location’s chapel might require you to stop and "nudge" the Image of The Patron God in the entryway, showing proper piety by stopping to reflect before entering the chapel.
* They may open when using an easy to find "right place". These doors will then slam the stone back in place (using a spring or sand and level mechanism). Some will slam when stepped through, others will wait a few moments and quickly roll shut automatically. Some of these are for security, others are simply door closers.
*A second "locking door" may roll or drop into place if the wrong door is opened the wrong way. Clearing these doors often required brute strength or a number of things to be tweaked to make it roll back.
*If a door’s weight if removed from its track (if removed or broken), this will often trigger a trap or locking door or heavy drop block.
*Getting in may be "easy", but out may be difficult. Especially if there is a timed trap involed to stop "interlopers" from entering the tomb.
*An reoccuring feature is the Hallway of the Gods. It is a hallway with a 22 doors, space every 8 feet for so. Each door has a touching challange. You must press the correct letters or pictographs to "answer" the common prayer. These answers can be memorized (okay 3rd door, we click here, here, here and over there) or if one knows the old tongue you select the answer to the classic prayer. However, in the Grey (late) Era, these Hallways were changed into "challanges of piety", so you needed to know the 22 gods and select the correct answer (requiring riddle or ancient lore checks). In the Grey Era selecting the insulting or wrong answer would set off an ironic trap.
In metagaming, these are great doors for two reasons. The first is that they are complicated. They will make players wary. The second, is that since they are "treasure", your PCs won’t go breaking them down.
The languages of the Norther use the term Pengoran for Pegoran, it is just a lingual quirk based on how the "Great Scribe of the North" decided to spell Pegoran in the Northern Root Tongue.