Here's a discussion of the alternation of day & night on the planet. Assume that, like the earth, the sun is so far away from the planet that sunlight can be approximated as parallel light. Parallel light shines on half of the hypersphere, leaving the other half in darkness. At this point, the morning & evening boundaries on the planet are upgraded to a sphere, dividing the hypersphere into a day-half hypersphere & a night-half hypersphere.
The alternation of day & night is caused by the planet's rotation; however, those living near the South & North Tracks perceive the day & night as completely different. The South Track is in the xy-plane, where the rotation speed is fast & has a short day, while the North Track is in the zw-plane, where the rotation speed is slow & has a long day. At mid-latitudes, the two rotation speeds simultaneously make the day longer or shorter each day, & the two types of circular motion are combined spontaneously, finally making the orbit of the sun unpredictable just like the Lissajous curve. If the ratio of the rotation speeds is an irrational number, the sun's trajectory will never be a closed orbit, but will be disordered like in a science fiction movie (but this is not a chaotic phenomenon; in fact, it is perfectly predictable).
When the nadir point of the sun is at mid-latitudes, there is no midnight sun or polar night, but at least one alternating day & night at each location. But how does the nadir shift with the rotation of the sun? On the earth, this depends on the ecliptic crossing angle (the angle between the ecliptic of the orbital plane & the earth's rotational plane). On the 4D planet, it also depends on the angle of intersection between the ecliptic & the equator. However, two planes in 4D space require two angular parameters to describe the positional relationship. Let t1 & t2 be the angles of the plane of revolution with respect to the xy-plane where the South Track is located, & 90-t1 & 90-t2 with respect to the zw-plane where the North Track is located (since the xy- & zw-planes are absolutely perpendicular, they are complementary angles to each other). The latitude of the point of direct sunlight is actually the angle between the line of the sun & the xy-plane at the South Pole. As the earth rotates, the direction of the line where the sun's rays are located changes constantly, & these directions are parallel to the plane of the orbital ecliptic. The two angles between the planes described above imitate the maximum & minimum line angles between all directions in one plane & all directions in the other plane, i.e., the points of direct sunlight vary only within a latitudinal range of t1 & t2 with a period of six months, with the points in this range being tropical & the rest of the world being arctic. This is the reason why the period when the sun is directly overhead at low latitudes is called the short-day period & the period when the sun is directly overhead at high latitudes is called the long-day period.
For a general revolution system, the angles between the ecliptic & the pole are between 0° & 90° & are not equal, so that there is at least one diurnal variation anywhere at any time. If the two angles of the ecliptic & the pole are equal (equiangular plane), there is no seasonal change for the entire planet.
Now to sum up: the short-day & long-day variations depend not only on the latitude of your location, but also on the latitude of the direct point of the sun (season), & the long-day & short-day variation is the result of the dual action of these two factors. It is necessary for people on this planet to use two calendar systems: long time & short time, there are two different time zone divisions. The difference in the length of time between the north & the south leads to the fact that people's biological clocks are different, & only people in the mid-latitudes can adapt to life everywhere, because the mid-latitudes are chaotic & have no rules.
Let's talk about a special type of double rotation called isoclinic rotation: if the xy-plane & zw-plane rotate at the same speed, then the short & long day have the same length, & more interestingly, due to the high symmetry of the isoclinic rotation, the trajectory of each point of rotation on the planet is a circle. (These circles fill the surcell of the glome to form the Hopf fiber bundle! All circles are isoclinic!) These circles are all in the same situation, & any of them can act as the North & South Tracks! It's a pity that there is not such a precise system in nature; it is more likely that the two rotational speeds are about the same, but differ just a little bit, which is enough to break the symmetry above & let us find the only South & North Tracks. Because there are both long & short times in the middle latitudes, this subtle speed difference will gradually accumulate, resulting in a long day-night & a short day-night dislocation. If the phase is completely opposite, the polar morning & evening phenomenon will be formed, & this phenomenon has a periodic nature & may be wrong back after a few days, It's the same as the physical principle of beat frequency.
There is never a beat rate phenomenon in the polar regions, & there is no beat rate when the sun hits the North & South Tracks directly, so this phenomenon is more extreme. In fact, whether the sun sets or not must be determined by both a short time & a long time, & the proportion of a short time & a long time is also determined by latitude & season, so the calendar system of civilization on the four-dimensional planet is really complicated.