# A yellow circle

A yellow circle
Released15 August 2006 (Update)
MembersYes
Quest itemThe Eyes of Glouphrie
Properties
EquipableNo
StackableYes
DestroyDrop
ExamineA yellow circular crystalline disc.
Values
Value1 coin
High alch0 coins
Low alch0 coins
Weight0 kg
Item ID9605

The yellow circle is an unobtainable item, intended to be obtained from Oaknock's Exchanger used in The Eyes of Glouphrie. It has a value of 3 in the elven machine as calculated by multiplying the value of the shape's colour and the number of sides the shapes have.

The yellow circle is unobtainable; it cannot be received from Brimstail. The exchanger will never give the player a yellow circle, due to the mathematical formula that it uses. If the puzzle requires a value of 3, a red triangle must be used instead.

## Oaknock's Exchanger

The exchanger uses a precise formula when selecting which tokens to give in exchange. Depending on the pieces put in, the machine must give a certain value in exchange. It will first select a random token greater than floor(n-1)/2 + 2, and less than the total value. This is subtracted from the required value, and the process is repeated with additional tokens being offered until the value offered in exchange matches.

If the final required value is 4 or less, the machine is fixed to always give the same result. If it needs a value of 4, it will always provide a green circle as opposed to a red square; if it needs a value of 3, it will always give the red triangle instead of the yellow circle.

The machine still has a possibility to give out these shapes as the second or third, rather than the final piece. The formula means that to give out a red square (and still have enough remaining to give a final piece), the required value must be 5 or 6. In order to receive the yellow circle, the required value must be 3 or 4 - but this is too low, as the machine is fixed at these values to always give the same result.

Because of this, the yellow circle can never be obtained.

Below is the value of each shape:
Colour Value
Circle Triangle Square Pentagon
Red 1 3 4 5
Orange 2 6 8 10
Yellow 3 9 12 15
Green 4 12 16 20
Blue 5 15 20 25
Indigo 6 18 24 30
Violet 7 21 28 35