No-one is entirely sure of course. But for me at least, the second side represents the importance of 10 as a number, by omission. 9 and 11, at either end, bracket 10; and 19 and 21, in the centre, bracket 20. Remember that 10 and 20 are very natural human numbers of importance, given our digits.

The third side is the most stunning. It gives 11, 13, 17 and 19 – the prime numbers between 10 and 20, in order. The remaining 7 and 5 on the first side extend the sequence of primes to include all the prime numbers below 20 occurring after 4… the first non-prime number.

The Ishango Bone

But the Ishango Bone contains three sets of numbers, in the forms of columns of scratches marked into its sides. Although there remains some academic uncertainty, it is thought that each of the three groups represents a depiction of the tribe’s knowledge of mathematical processes – astonishing, given the era. The first column is the plainest. There is a 3 next to a 6, a 4 next to an 8, and a 10 next to a 5, along with a further 5 and a 7. Leaving aside the last pair for the moment, these pairs clearly indicate multiplication by two.

What mathematical processes would you guess that the other two sides indicate, and where do the remaining 5 and 7 from the first side fit?

Update:

So. The Ishango Bone.

The second side represents the importance of 10 as a number, by omission. 9 and 11, at either end, bracket 10; and 19 and 21, in the centre, bracket 20. Remember that 10 and 20 are very natural human numbers of importance, given our digits. The third side is the most stunning. It gives 11, 13, 17 and 19 – the prime numbers between 10 and 20, in order. The remaining 7 and 5 on the first side extend the sequence of primes to include all the prime numbers below 20 occurring after 4… the first non-prime number.

Sunset in Criação Velha, Pico Island Azores by Ulrich Thumult

In “A Pattern of Islands” by Arthur Grimble, a British colonial officer wrote about his early career stationed in the Gilbert & Ellis Islands of the South Pacific at the start of the 20th century. In one fascinating chapter, he tells how the natives of one island decide to throw a huge feast, at which the food is going to be large fish. Rather than let the fishermen actually go out and actively hunt the fish, the village shaman went to sleep, and entered a lucid dream. He then located a school of fish from within his dream. Once he had found them, he moved himself to them in the dream, and politely asked them to come to the beach which his hut was upon, so that the villagers could eat them. In return for their selfless generosity, he promised the fish that they would be honoured guests at the feast at which they were served.

The shaman then woke up, and told Grimble about the dream. A few hours later, Grimble was shocked to see a number of large fish swim straight into the bay and as far up into the shallow waters as they could get. They then remained passively in the water while the fishermen of the village went amongst them, slaughtering them and dragging the carcasses up onto the beach to prepare them for the feast at which they would be both honoured guests and main course.

But it gets stranger than that. There are stories of a small Indonesian tribe in which all the people shared a common dream. Every night, all the people would dream of the same city, a wondrous place of islands covered with tall, thin spires and connected by airy walkways. The astounding fact is that during these dreams, all the people were fully aware of all the other dreamers, and could interact with them normally. When they awoke the following morning, they would all remember exactly what had happened, and what they had said to whom, as would those people they had talked to. In effect, life continued as if they were awake, but just in a different location.

Just imagine what might be achieved if we could harness our dream-time on an everyday basis…

Blood flushing to the skin can signal excitement, anger, sexual arousal, embarrassment and other moments of intense emotion – critically important signals to those around us. The presence of blood itself is a strong instinctive alert. It means that someone or something has been injured, possibly killed: the danger could still be present… or there might be vital food on a freshly-hunted carcass.

Although most individual flames shade across several colours, fire is red in our minds and our symbolic languages. Like blood, it is both life-giving and lethal, a vital source of warmth and nurture, but also a clear reminder of pain and death. Harnessed fire is energy and power – light to live by, heat to cook and get warm by, a weapon to drive off enemies with. It was the vital tool that allowed us to develop the society and intelligence that we have today.

Rojo Sobre Negro by -Merce-

From these critical foundations, red has taken on a complex web of meanings for us. Because of its strength, it represents power, force, leadership and courage. With the way that it colours our skins to reflect our emotions, it is also associated very strongly with sexuality, passion, excitement and love, and with defensive reactions such as anger, aggression, rage and shame. Through its links to fire, it carries meanings of energy, force and destruction, material security, stability and influence. Modern society has given it meanings that include debt (from the red ink used to mark ledger debits), left-wing politics, and the instruction to stop. Blood gives the colour its deepest associations, to life and death, birth, menstruation, violence, danger, war and excitement. Above all, red is exciting, getting us ready for opportunity or threat, the joint thrills of pleasure and danger.

Across the world, culture-specific beliefs tend to reinforce the general human experience of the meaning of red. In classical times, the planet Mars, the brightest red light crossing the sky, was identified with (and named after) the Greco-Roman God of War. Heraldry used red to indicate boldness, ardent love and enthusiasm. For the Chinese, red is the colour of luck, because of its power over life and death. Across much of Africa, it is seen as one of the colours of sorcery, because of the power of blood. In Polynesia, it is the colour of the gods themselves. In India, it represents virginity and purity. Christian belief associates it with Christ’s martyrdom, while Hindu thought attributes it to the power of Kundalini, the sacred life-force.