The three redmarked glyphs are simple toa glyphs without any obvious further signs. However, the creator of Tahua was subtle - signs there are. First we notice the distribution with 2 toa before midnight (Aa1-43) plus 1 after. Then we can perceive that Aa1-44 is slightly different from Aa1-40 and Aa1-42.

Considering the other triplets of glyphs with toa included (Aa1-37--39 respectively Aa1-46--48) we see that also the toa part in Aa1-38 is different from the other two. It is sligthly slimmer and has (like Aa1-44) a little gap at right in Y.

And then we notice how also Aa1-40 is slightly slimmer than Aa1-42. The two toa framing midnight (Aa1-43) are the sturdiest. Finally, now that we have been trained in the task, we can immediately identify toa in Aa1-46 as different from the other two in the last of the triplets.

The meaning of these small, hardly noticeable, signs cannot be ascertained without a thorough knowledge of the basic meanings of the rongorongo signs - far beyond our capability for the moment.