Turns out that "Catena" is a chain or connected series. Found it out by looking up synonyms for "chain". You learn something new everyday.
The large version can be seen at the preceding link.
Today's Gratitude Item: My new computer arrived today!! It is a truly wonderful thing. Everything is "up and running" except for my printer / scanner which I could not connect because I need a USB adapter / cable to connect them up. The new machine has loads more internal memory than the old one which is really important when one is rendering large graphics. Best thing about this experience is the speed with which the new computer arrived. Was only expecting it some time next week yet it arrived first thing this morning.