Kuf is the nineteenth letter in the Alef Beis. It represents the shleymus of 10 in terms of Hashem's hashpa'ah towards us, vs. our imperfect 9 - כקוף בפני אדם - There are shittos that nine people in a room that look like ten constitute a minyan but it is actually a poor parody.
Reish is the twentieth letter, thus representing a full array of zeh l'umas zeh - but without a connection, Reish therefore always represents that which breaks apart or splits open.
Shin is the 21st letter - it has a connector - 10+1+10. That is represented by the middle pen-stroke. It is used by Chazal (as 300) for a number that captures the ultimate wholeness in Olam HaZeh.
Taf is the 22nd letter. This is 10+1+10+1 = the short pen-stroke on the left bottom of the Taf represents the capacity to look beyond, much as a shalem will seek to be mashpi'a.
The tikkun of this letters is the reverse order in which they form the acrostic of many piyutim. The shefa should flow from the beyond to our system, neutralize the duality, and provide an impetus for the mimic to internalize.
More to come, IY"H