Figure 1. This pattern is very useful at the singer's 
pause or at the end of a   cadenza, although you can 
play it through the whole song.

Figure 2. You can also syncopate by a 16th note.

Musical exemples:

Example 1 is based on a asmba pattern, with an 8th 
note syncopation, and uses "variation #4" in the last 2 
measures. Again the chord changes are pretty 
common in bossa nova songs and you can use them 
in many different tunes of the Brasilian music repertoire.

Example 2 Here we have another example of a 
reharmonised I-VI-II-V turnaround. Its rhythmic pattern 
is based on "variation #4" with a 16th note 
syncopation between the 2nd and 3rd measures. 
Notice that the harmony changes a 16th note before 
the syncopated note.

Example 3 applies the pattern "variation #4" to the last 
16 bars of "Samba de uma nota so" ("One Note 
Samba") by Antonio Carlos Jobim and Newton 
Mendonca, using rests on the first beat of the 
measures and on the bass line. Notice that the chord 
changes in the last beat of the measure.

Example 4 is a tranacription of the rhythm guiutar part 
played by Joao Gilberto on the introduction of the song 
"Esse seu olhar" (Tom Jobim), as recorded on the 
album "Joao Gilberto" EMI-Odeon, 1961. It uses the 
bossa nova pattern "variation #4" in the last two bars.