Final answer:
In flowcharts, a rectangle symbolizes a process and a diamond represents a decision. The diamond indicates a branching point where the path diverges based on a binary choice.
Step-by-step explanation:
The rectangle icon in standard flowcharting symbols represents a process item, which is a step where an operation is performed or a calculation takes place. On the other hand, a diamond shaped icon is used to represent a decision item in flowcharts. This decision symbol indicates a branching point where the flowchart splits into different paths based on a yes/no question or true/false test. The image described as showing the progression of achievements through three arrows pointed right is likely a simplified representation of a process or sequence of actions rather than the specifics of flowchart symbols.