This canon is departing from the regular form in two ways. The time in which the second entry sets in, is very short. So the phrase is not finished or presented in unison, but is imideately imitated.
The second way in which this canon is different is that each phrase is not repeated in the same interval distance. For example, bar 1 and 2 the second entry is an octave and minor third higher, while in bar 3 an octave and a major third, in bar 4 an octave and a forth, and so on…

The result is an imitative texture that explores some of the harmonic consequences of shifting the interval of the entries.