Summary
As you may notice all this consonants are connective (change
shape in order to connect to the letter following them)
Another thing is that b is written like t and is differentiated
only by dots (one dot under b, two dots above t)
k at the end of the word can be written in two ways
or but
the latter is used most commonly used in the holy Quran
This table summarizes the various forms of the letter in
different positions in a given word: