Analysis of the Taï plaque, the most complex Upper Palaeolithic composition, has revealed evidence of the problem-solving and visual cueing strategies involved in the accumulation of the marks. The composition consists of a boustrophedon sequence of short horizontal containing lines or sections, each of which carries irregular subsets of marks. The analysis proceeded in stages over a period of twenty years, initially with use of a microscope, but did not involve cross-sectional analysis or counting. The theoretical assumption guiding the analysis was that notations represent a cognitive form of visual problem-solving and structuring. A test of the sequence of containing lines and their subsets of marks suggested the notation on the Taï plaque was a non-arithmetic form of lunar/solar observational recording. The analysis, if validated, carries profound implications for our understanding of Upper Palaeolithic culture, and cultural features of the indigenous European population in the periods that followed.