# Rainbows Everywhere

There are rainbows in windows, and on buildings, all round the world at the moment so I went looking for all the rainbows we have ever made. I surprised myself when I realised how many we have. Some of them are not rainbow-shaped but they are rainbow colours.

Scroll to the bottom to see what we currently have in our window.

Some Square Over The Rainbow

This blanket was made way back in 1997. It is obvious that it has the seven colours of the rainbow and it has 49 small squares in 7 columns and 7 rows. They represent square numbers and one way of calculating them.

Each colour has an odd number of squares. There is one violet square, 3 indigo, 5 blue, 7 green, 9 yellow, 11 orange and 13 red, making the total of 49. Square numbers are the sum of odd numbers.

The first square number is 1.
The second is 4 (2 x 2), which is 1 + 3.
The third is 9 (3 x 3), which is 1 + 3 + 5.
… and so on
The seventh is 1 + 3 + 5 + 7 + 9 + 11 + 13 = 49

Wheely Colourful

Is this rainbow curved? You might think so but each triangle has straight sides until the next one is joined to it.

It is a fun afghan, knitted on straight needles and made entirely from scraps.

It has hundreds of knots, left showing. A few knots look like a mistake; lots of them become a design feature.

I divided all my DK weight oddments into seven piles. It was sometimes difficult to decide which pile a particular yarn should go into. Looking at a pile with half-closed eyes made it easy to spot anything that was seriously out of place. I then tied lengths together to make seven large balls.

Double Vision

This is not quite a rainbow because it uses ten colours.

Yes, it really does only use ten colours of yarn, though you can see 55 different shades from the mixes of those yarns. It shows all the possible combinations of ten colours.

Alternative Rainbows

In 2018 we were involved with a maths project called Mirror Pillar, using anamorphic art. Anamorphic designs look completely different when you reflect them in a cylindrical mirror. We made several large pieces to accompany the pillar on its travels round the country. We also made some rainbows. They are not all the shape you would expect and they give even more unexpected shapes when they are reflected in a cylinder.

Barbie Rainbows

Barbie likes rainbows too.

Her rainbows are a little unconventional. The two long dresses have stripes that get wider. There is one violet ridge of knitting, two indigo, three blue, etc.

The short skirt forms a circle with seven sections when it is flat.

Rainbow Spinners

You probably made these spinners out of cardboard when you were a child. A few years ago we made lots of knitting and crochet versions in all kinds of colour combinations. Four of them were rainbow colours.

I didn’t write a pattern at the time but have now written outline instructions for making them.

Tower of Hanoi

The Tower of Hanoi is a mathematical game or puzzle, which can also be used as a simple stacking toy for a young child. A number of rings are arranged, on a post, in size order, to form a tower. There are two spare posts. The object of the game is to move all the pieces onto another post to form a new tower, with the pieces in the same order as the original. The rules are

• Only one ring may be moved at a time.
• A ring can be moved onto any rod and placed on top of the pieces that are already there.
• No ring may be placed on top of a smaller disk.

Some Wear Over The Rainbow

Seven crochet cords fastened together to make a rainbow scarf.