Values, names, decisions, and loops

A variable is a name for a value during a run. The first statement stores the number 2 under score. The second statement reads it. Storing and displaying are different operations; the set block can work correctly without printing anything.

The rounded score value belongs inside the output socket. The word Score in the label field is ordinary text for the reader. Those two similar-looking words have different jobs.

Add set from Basics, name it score, and enter 2. Under it add a labelled say, type Score as the label, and insert the rounded score variable into the value socket.

Change score by 3 reads the old score, adds three, and stores the result back under the same name. It does not create a second score. The computer follows the stack from top to bottom, so the final output sees five.

This is also how a game score works: a running value is updated when something happens. If you put the first set block after the change, it would overwrite the result with two.

Insert change score by 3 between the assignment and output. Check the insertion line before releasing the dragged block. Keep the set block above the change.

A comparison answers a yes-or-no question with one of two values: True or False. Programmers call a true-or-false value a Boolean. Here the operator >= means greater than or equal to, so exactly five counts as True. The comparison is a value block, so it needs an enclosing instruction to do something visible with its result.

The comparison reads the variable; it does not change it. In Python the same question will be score >= 5. You are already choosing the calculation before learning its typed punctuation.

Put a comparison in the labelled output socket. Put score on its left, choose >= in its menu, and type 5 on its right.

An if/else uses that True or False answer to decide which body to run. With score five it enters the first body; with four it enters otherwise. After that body finishes, execution continues below the whole if/else.

Indentation in the illustration shows ownership. A say placed below the closing edge would run regardless of the comparison. A say placed inside otherwise runs only when the comparison is false.

Move the comparison into the if/else test socket. Put Ready inside the first opening and Keep practising inside otherwise.

AND is true only when both comparisons are true. A high score alone is not enough, and a ticket alone is not enough. Build each comparison first, then put those two completed value blocks inside the logic block.

The word yes here is an ordinary text value; the comparison converts the question about that text into True or False. Equality checks whether the stored text matches. It does not set has_ticket to yes.

Nest score >= 5 and has_ticket is yes in the two AND sockets, then put AND in the if test.

A running total needs an initial value before the loop. Each turn adds two to the value left by the previous turn. Follow the values: zero before the loop, two after the first turn, four after the second, six after the third.

Now is inside the loop and prints every turn. Finished is below the loop and prints once. Repeated output is a useful trace while you are learning or debugging.

Create total before repeat. Place change and Now inside repeat, and Finished below its closing edge.

A list keeps values in a particular order. Creating an empty list and appending three items gives rock, then paper, then scissors. The name moves refers to the whole collection, not one particular move.

The item block uses friendly positions beginning at one. Python lists will begin at zero; the generated code translates the block position. The length is a count, so three items still means a length of three in either language.

Create moves from Lists. Connect three add blocks in order, then place item 1 of moves inside the output socket.

For each creates the name move for the current item. On the first turn move is rock; on the next it is paper; on the last it is scissors. The loop handles the number of turns based on the list.

Use the rounded move variable inside the body. Typing move as text would print the same word three times. The final message sits outside the body so it is a single completion message.

Add a for-each block, select moves, and name the loop item move. Nest a labelled output reading move inside it.

When this stack reaches its text question, Terminal pauses and waits for an answer. Type a fictional name, then press Enter or Send. It then waits again for the number block; type a numeral for the age and send it. Each answer reaches one asking block in order, and the number answer becomes usable in arithmetic.

An empty or nonnumeric age cannot be converted into a number; that is an input problem, not evidence that addition is unreliable.

Press Run. When Terminal first waits, answer with a fictional name. When it waits again, answer with a number. Watch the stack resume after each answer.

This tiny fictional story launcher uses the same four ideas together. It reads two Terminal answers, selects a story branch, then counts down. The age rule belongs to this invented story; it is not an account-access or safety rule.

Read the complete stack in sections before running. The first Terminal answer determines the greeting and the second determines the story branch. Countdown starts at three and is independent of age. Keeping those jobs under distinct names makes the flow easier to explain and debug.

Build the two input assignments, the branch, and the countdown in order. Keep the initial countdown outside repeat. Press Run, answer when Terminal waits twice, then personalise the answers on another run.