Visualized
Visualizations
Every interactive figure across the cheat sheets in one place — animated 2D explainers and orbitable 3D simulations you can step through.
3D simulations
12 figuresOrbit, zoom, and step through how it works — rendered in real WebGL.
C — the call stack & the heap (3D)
3DStep through a program: stack frames push/pop while a malloc'd heap block outlives its function — then dangles after free().
C →
Docker — image layers & containers (3D)
3DAn image is a stack of read-only layers; each container adds one thin writable layer on top (copy-on-write).
Docker →
Network — encapsulation across the layers (3D)
3DEach layer wraps the payload in another header — data → segment → packet → frame — then the receiver peels them off.
Networking →
Kubernetes — scheduling & rolling update (3D)
3DThe scheduler spreads replicas across nodes; a rolling update swaps v1→v2 one at a time; a failed node reschedules its pods.
kubectl →
Binary search tree — search (3D)
3DEach comparison goes left or right, halving the search space — O(log n).
Data structures & Big-O →
Virtual memory — paging (3D)
3DThe MMU maps each contiguous virtual page to any scattered physical frame via the page table.
Linux admin →
Consistent hashing — the ring (3D)
3DKeys belong to the next node clockwise; adding a node remaps only ~1/N of the keys.
System design →
Neural network — the forward pass (3D)
3DActivations flow forward layer by layer; each neuron is a weighted sum of the previous layer + an activation.
Full-stack + AI skills →
Raft — leader election & log replication (3D)
3DOne elected leader serializes writes; a log entry commits once a majority of nodes replicate it.
Microservices →
CPU cache — the memory hierarchy (3D)
3DEach level down is ~10× slower but bigger; caches exploit temporal & spatial locality, so a repeat access is fast.
C →
Garbage collection — mark & sweep (3D)
3DLiveness = reachability from the roots; anything the GC can't reach is swept (not reference-counting).
TypeScript →
TLS handshake — key exchange (3D)
3DSlow public-key crypto authenticates the server and agrees a fast symmetric session key; bulk data uses that.
Network security →
Animated figures
35 figuresPlay or step through the concept; watch it move instead of just reading it.
Stack — LIFO
Push and pop from the top.
Data structures & Big-O →
Queue — FIFO
Enqueue at the back, dequeue from the front.
Data structures & Big-O →
Big-O growth
How the number of operations scales with input size.
Data structures & Big-O →
Sorting — bubble sort
Watch comparisons and swaps; the sorted tail grows green.
Data structures & Big-O →
SQL JOIN
How INNER / LEFT / RIGHT / FULL combine two tables.
SQL →
TCP 3-way handshake
SYN → SYN-ACK → ACK before any data flows.
Networking →
Version ranges
Which published versions ^, ~, and exact actually accept.
Semver →
Merge vs rebase
Same commits, two histories: merge records a merge commit; rebase replays them linearly.
Git →
Live regex matcher
Toggle a pattern and watch what it matches — greedy vs lazy on one string.
Regular expressions →
HTTP flows
304 revalidation and CORS preflight, step by step.
HTTP headers →
BST traversals
In-, pre-, and post-order over a binary search tree.
Data structures & Big-O →
Hash table
hash(key) % N picks a bucket; collisions chain.
Data structures & Big-O →
Binary search
Halve the range each step to find a target in O(log n).
Data structures & Big-O →
Linked list
Insert and delete by re-pointing next.
Data structures & Big-O →
Rolling update
A new pod goes Ready before an old one is removed — zero downtime.
kubectl →
Markdown → preview
Toggle a snippet and see the source render.
Markdown →
Image layers & build cache
Change a file and watch which layers rebuild.
Docker →
LRU cache
The least-recently-used entry is evicted when the cache is full.
System design →
JWT anatomy
header.payload.signature — base64url, and what each part holds.
Network security →
OAuth 2.0 — Authorization Code + PKCE
The front- and back-channel flow, and why an intercepted code is useless.
OAuth 2.0 & OIDC →
Bash — a pipeline (stdout → stdin)
Each command's stdout becomes the next command's stdin — watch the stream narrow to a single count.
Bash / shell →
Vim — modal editing
Keys mean different things per mode; Esc always returns to Normal.
Vim →
Testing — the pyramid & the TDD loop
Many fast unit tests at the base, few slow E2E at the top — plus the red → green → refactor loop.
Testing strategy →
Redis — key expiry (TTL)
Keys set with EX expire when their countdown hits zero; a GET then returns nil.
Redis →
nginx — reverse proxy & load balancing
nginx terminates TLS and forwards each request to an upstream server, round-robin.
Nginx →
GitHub Actions — the job DAG
needs: orders jobs; independent jobs (test ∥ lint) run in parallel.
GitHub Actions →
Linux — file permissions (rwx ↔ octal)
Each octal digit is r(4) + w(2) + x(1) for owner, group, other — toggle the bits and watch chmod update.
Linux admin →
Terraform — plan → apply → state
plan previews a diff against state; apply reconciles real infrastructure to match the config.
Terraform →
Postgres — index vs sequential scan
A sequential scan checks every row (O(n)); a B-tree index takes a few guided hops (O(log n)).
PostgreSQL →
Python — list slicing [start:stop:step]
stop is exclusive, step can reverse with -1, and negative indices count from the end.
Python →
TypeScript — type narrowing
Control-flow guards (typeof, ===, in) shrink a union to one specific type per branch.
TypeScript →
OpenAPI — request validation
The schema is the contract — the server rejects any request that doesn't satisfy it.
OpenAPI & REST →
Digital logic — a clocked timing diagram
Synchronous logic only changes on the rising clock edge; reset forces a known state.
VHDL →
8051 — bit-addressable port (P1)
SFRs like P1 are bit-addressable — flip one pin (SETB / CLR) without touching the others.
8051 (MCS-51) →
RAG — retrieval-augmented generation
Embed the question, retrieve similar chunks from a vector DB, and ground the LLM's answer in your data.
Full-stack + AI skills →