We like to refer to the A7 figure as the triangle (simply because of the shape it makes when marking it). This figure is rather simple to play in it’s first position when marking the A7 chord, but can cause complications when applying it along the rest of the Cuatro. The main reason for this is because of the application of the pinky which needs to be placed in a rather unnatural way. Take a closer look at some chords making use of the A7 figure:
With 7th figures we can make use of the same theory applied to the figure of D Major. In order to mark another chord relating to a different note, it is a matter of rolling down the bar applied with the index finger the number of frets or halftones until your desired note is found. By using the B7 as an example, we know that the distance between A and B is 2 halftones. Imagine when playing the A7 chord that there is an invisible bar starting from the nut on the top of your Cuatro. This we then take and slide down to the first fret (the result being an A7#) and then one more halftone which would result in the B7 chord in it’s second position.
Take a look at how this is applied on the Cuatro below:
If we were to apply the same concept to find other chords, then essentially you will be able to play any 7th chord with the Cuatro providing that there is enough space to find the note, given that most Cuatros have 15 – 17 frets. Give this a try and find other chords corresponding to other 7th notes making use of the figure of A7 or triangle. Here is the chord of D7 in it’s 3rd position to get you started.