Interactive concept examples

Change an input, advance one step, inspect the visual state and read why it changes. Reset and compare another case. These examples supplement the 30 course investigations and are available from the related course and pilot lessons.

Aligned to the current 2026–27 framework. Model completion is practice; explaining, building and testing your own work develops the wider skills.

• Topic 1.1

  Pair programming and shared review

  Diverse perspectives · Driver and navigator · Shared tools and conflict resolution

• Topic 1.2

  Purpose, events and observable output

  Purpose versus feature · Event-driven execution · Input, processing, state and output

• Topic 1.3

  Iterative development and documentation

  Requirements and prototypes · Incremental versus iterative work · Comments, documentation and acknowledgement

• Topic 1.4

  Locate syntax, execution and logic errors

  Error classification · Expected versus observed output · Distinguishing tests and regression

• Topic 2.1

  Sampling, precision and bit interpretation

  Analog versus digital · Sample intervals and rounding · Bits, bytes and conventions · Fixed-width versus AP integer model

• Topic 2.2

  Decode losslessly or discard information

  Dictionary reconstruction · Lossy collisions · Purpose and recovery requirements

• Topic 2.3

  Metadata, association and linked data

  Metadata versus primary data · Descriptive claims versus causes · Combining records and re-identification

• Topic 2.4

  Join, transform, classify and scale data

  Keys and unit conversion · Normalisation · Transformation and classification · Tool capacity and scaling

• Topic 3.1

  Value types and independent copies

  Names versus values · Number, string, Boolean and list · Copy then update

• Topic 3.2

  Grow a collection without rewriting the algorithm

  List order and duplicates · Generic traversal versus separate variables · Preserving associations

• Topic 3.3

  Precedence, division, MOD and sequencing

  Arithmetic precedence · Parentheses and reordering · Numeric addition versus concatenation

• Topic 3.4

  Join exact strings and preserve spaces

  Text digits versus numbers · Concatenation and length · Literal spaces and leading zeros

• Topic 3.5

  Relations, truth tables and NOT

  All six relational operators · AND, OR and NOT · De Morgan equivalence and assignment

• Topic 3.6

  Independent IFs versus IF/ELSE

  Multiple outputs in order · Exclusive branches · Inverted equivalent conditions

• Topic 3.7

  Reachable and contradictory nested paths

  Outer branch before inner branch · Unreachable conditions · Path coverage

• Topic 3.8

  Counted loops, accumulator and output placement

  REPEAT n TIMES · Initialisation placement · Display inside versus after · Early return and zero iterations

• Topic 3.9

  Build algorithms from running summaries

  Minimum and maximum · Sum and average · Divisibility and composition

• Topic 3.9

  Robot commands, orientation and obstacles

  Sequencing, selection and iteration · MOVE_FORWARD and turns · CAN_MOVE and grid paths

• Topic 3.10

  Read, replace, append, insert and remove

  AP one-based indexing · Python index comparison · Index shifting · Invalid access terminates

• Topic 3.11

  Choose linear search or binary search

  Unsorted versus sorted data · First match versus some match · Measured comparisons versus worst case

• Topic 3.12

  Call, return, display and resume

  Argument binding and local calls · RETURN ends the call · DISPLAY is not a returned value

• Topic 3.13

  Refactor copies and test meaningful parameters

  One shared definition · Modularity · Ignored parameters and compatible calls

• Topic 3.14

  Library contract and compatible replacement

  Documented arguments, ranges and returns · Implementation versus interface · Integration and version tests

• Topic 3.15

  Inclusive random ranges and expected outcomes

  Inclusive integer bounds · Exact event probability · Expected count is not a guarantee

• Topic 3.15

  Fair positions, duplicate labels and removal

  Inclusive RANDOM bounds · Category probabilities · Sampling without replacement · Empty-list guard

• Topic 3.16

  Simulation assumptions and event order

  Abstraction and omitted factors · Arrivals before or after service · Controlled comparison and variability

• Topic 3.17

  Loop work, factorial growth and heuristics

  Consecutive versus nested loops · Polynomial, exponential and factorial growth · Decision versus optimisation · Heuristic limits

• Topic 3.18

  A problem, an instance and a general algorithm

  Decidable versus impractical · Individual versus general halting · Restricted domain and infinite loops

• Topic 4.1

  DNS, IP, TCP/UDP and Web services

  Devices, systems and networks · Open protocols and scalability · DNS naming versus trust · Web versus Internet · Reliable delivery versus best effort

• Topic 4.1

  Bandwidth is capacity; latency is delay

  Bits and bytes · Bits per second · Capacity versus startup delay

• Topic 4.2

  Test every single failure and combined failures

  Redundancy and resource cost · Single-link versus multiple failures · Endpoint isolation

• Topic 4.3

  Serial work limits parallel speedup

  Sequential, parallel and distributed · Unavoidable serial portion · Communication overhead and capacity

• Topic 5.1

  Intended benefits and unintended reuse

  Physical, software and conceptual innovations · Benefits, harms and scale · Creative expression and cross-field effects

• Topic 5.2

  Overlapping access barriers

  Device versus effective access · Connectivity, skills and opportunity · Individual, organisation and government action

• Topic 5.3

  Locate bias before choosing a mitigation

  Sampling, labels, rules and deployment · More data versus better representation · Evaluate group outcomes after change

• Topic 5.4

  Citizen science, shared computation and funding

  Distributed human contributions · Citizen science · Crowdfunding and scientific collaboration

• Topic 5.5

  Consent, purpose and a less intrusive alternative

  Consented versus proposed data use · Different recipients · Legal permission versus ethical judgement

• Topic 5.5

  Open resources, acknowledgement and conditions

  Intellectual property and plagiarism · Creative Commons, open source and open access · Attribution versus permission

• Topic 5.6

  Symmetric keys, public keys and certificates

  Encryption versus authentication · Shared-key versus key-pair roles · Certificate trust and endpoint limits

• Topic 5.6

  Count factor categories, not password prompts

  Strong secrets and authentication · Knowledge, possession and inherence · MFA limitations

• Topic 5.6

  Link records, retain history or minimise collection

  Direct and indirect identifiers · Search, browsing and location history · Linkage, retention and onward sharing

• Topic 5.6

  Phishing, malware and protection boundaries

  Keylogging and deceptive links · Rogue access points and interception · Updates, scanning and permissions