John Williams always uses a a pattern rupture on the beat number 4 for his melodies' patterns.
This way he creates a pattern that is resembled in all the movies' themes.
Of course: he adds other elements to each theme.
But it is the breaking point on beat number 4 that gives cohesion and unity to all his compositions in all musical melodies he creates.
For the "Main Theme" he uses a quarter note tuplet and repeats it again in each 4th beat.
For "Tales of a jedi Knight" he uses a pair of 16th notes at the fourth beat and on the next 4th beat he uses the characteristic quarter note tuplet.
For the "Imperial March" he uses a Eb - Bb cell for the pattern rupture on the melody being previously written in the G note.
This way he creates a pattern that is resembled in all the movies' themes.
Of course: he adds other elements to each theme.
But it is the breaking point on beat number 4 that gives cohesion and unity to all his compositions in all musical melodies he creates.
For the "Main Theme" he uses a quarter note tuplet and repeats it again in each 4th beat.
For "Tales of a jedi Knight" he uses a pair of 16th notes at the fourth beat and on the next 4th beat he uses the characteristic quarter note tuplet.
For the "Imperial March" he uses a Eb - Bb cell for the pattern rupture on the melody being previously written in the G note.
The same happens with these two following musical themes composed by John Williams: