Play with Patterns - Coding and Decoding Messages

A pattern is a series of numbers, letters, or symbols that repeats or grows according to a specific rule. For example, a visual pattern might show a sequence like $\triangle, \square, \triangle, \square$, where the rule is alternating shapes.

Coding is a method used to send secret messages by replacing letters or numbers with other symbols or values. A common visual for this is an alphabet-number table where 'A' is paired with $1$, 'B' with $2$, and so on up to 'Z' with $26$.

In Letter-to-Letter coding, each letter in a word is replaced by another letter based on a fixed rule, such as shifting forward by one position ($+1$ shift). Visually, this looks like two alphabet lines where the bottom line is shifted: 'A' becomes 'B', 'B' becomes 'C', and 'Z' loops back to 'A'.

Decoding is the reverse process of coding. If a secret message was made by shifting letters forward by $2$, you must shift them backward by $2$ to read the original message. For example, if 'C' is the code, the decoded letter is 'A' because $3 - 2 = 1$.

Reverse Alphabet Coding is a pattern where 'A' is replaced by 'Z', 'B' by 'Y', and so on. This follows the mathematical logic that the sum of the positions of the original letter and the code letter is always $27$. Visually, you can imagine the alphabet written forward and then backward underneath it.

Number Patterns in coding involve sequences where numbers increase or decrease by a fixed amount. For instance, in the sequence $5, 10, 15, 20$, the rule is to add $5$ each time ($+5$), which can be visualized as jumping forward on a number line.

Symbol Coding uses unique shapes to represent specific letters. For example, a message might look like a series of geometric shapes like a circle, a star, and a heart, where each shape corresponds to a letter like 'S-U-N'.