Squares, Rectangles & Rounds in Fall Colors: The Key!

A while back I presented a colorful graph. I suspect most folks figured some of it out. As you know from earlier posts, I like to use shapes as a starting point for classifying CTs from Scotland. When the shapes are tallied across time, interesting trends (and regional variations) come to light.
     So here is the key to the puzzle. The first two colors are squares, rectangles & rounds. The squares and rectangles were grouped together and given a deep brick red. But the rounds stand alone and are of lighter color. These were among the earliest pieces.

Some early squarish ones, or should
we call some of them rectangular?

     Yes, hearts appeared early too, but they did not last long and would only produce a sliver on this graph. Odd shaped CTs with unequal sides also arrived early on, but these were anomalies and barely merit a space on this graph. If I put them in with green hues then we might see them.
     The squares and rectangles were grouped together since they are closely related. In fact, some tokens are squarish due to one uneven or scalloped side, or else they are barely rectangular with a difference of one millimeter. Burzinski liked to sharply differentiate the shapes as one or the other, whereas Brook used the term "squarish" here and there.
     Some pieces had square designs on slightly rectangular flans. Certainly, some pieces were clearly elongated with relaxed spacing of letters and numbers or with three lines of data -- true rectangles! In any case, you can see the big area taken up by these two right-angled CT forms.

Roundish and Round.

     The rounds became less popular over time and never rivaled the right-angled pieces. However, they remained in use until the end when they were about as popular.
     Can you figure out the other colors? If not hearts or octagons, then what? Hint: just look at the key.
     Of course I am referring to the modern shapes. For starters, we have to give the cut rectangle its own category, as these became the most popular type. And so here they are, showing a "slim" beginning. Despite the puny start, they began to assert themselves at the start of the nineteenth century. Cut rectangles became dominant at the end.
     So what is left? The oval of course! And, as you can see, the oval had its day! It dominated briefly, coming on strong in the late eighteenth century. It was quite popular at the turn of the century. The oval was eventually eclipsed, but remained popular.
     In the end, the big pieces took over: rotund ovals and broad cut rectangles. All the data could be squeezed on the obverse, leaving the reverse for a Bible verse.