All Learning Pathways

block.hash = sha256(prevHash + data + nonce)
while (!block.hash.startsWith('0000')) nonce++

prompt = "Explain gas fees like I'm 12"
response = model.generate(prompt)
print(response)

function mint(address to, uint id) external {
  _safeMint(to, id);
  emit Minted(to, id);
}

function withdraw() external {
  uint amount = balances[msg.sender];
  balances[msg.sender] = 0;
  payable(msg.sender).transfer(amount);
}

l1.postBatch(rollup.compress(1000_txs))
// 1000 transactions, 1 L1 fee

function swap(uint amountIn) external {
  uint out = (amountIn * reserveOut) / (reserveIn + amountIn);
  reserveIn += amountIn; reserveOut -= out;
}

rsi = compute_rsi(prices, period=14)
if rsi < 30: signal = "oversold"
elif rsi > 70: signal = "overbought"

function payAgent(address agent, uint task) external {
  require(oracle.verify(task), "unverified work");
  token.transfer(agent, bounty[task]);
}

function equipSword(uint tokenId) external {
  require(ownerOf(tokenId) == msg.sender);
  player.equipped = tokenId;
}

proof = zk.prove(secret, statement)
assert zk.verify(proof, statement)  // true, secret never revealed

function trade() external {
  require(block.timestamp <= deadline);
  require(amountOut >= minAmountOut, "slippage");
}

SYSTEM: You are a senior copyeditor. Be concise and direct.
USER: Rewrite this sentence for clarity.
Text: "The utilization of the aforementioned methodology..."
Think step by step, then give only the final rewrite.

X_train, X_val, X_test = split(data, ratios=[0.7, 0.15, 0.15])
model.fit(X_train, y_train)
val_score = model.evaluate(X_val, y_val)
# Only after tuning is done, touch the test set once
test_score = model.evaluate(X_test, y_test)

output = activation(sum(weight_i * input_i for i, input_i in enumerate(inputs)) + bias)
loss = loss_function(output, target)
gradients = backpropagate(loss, network)
weights -= learning_rate * gradients

while not task_complete:
    observation = get_current_state()
    thought, action = model.decide(observation, goal, history)
    result = execute_tool(action, sandbox=True)
    history.append((thought, action, result))
    task_complete = check_goal_reached(result, goal)

query_vector = embed("What's our refund policy?")
top_chunks = vector_db.search(query_vector, k=4)
context = "\n\n".join(chunk.text for chunk in top_chunks)
prompt = f"Answer using only this context:\n{context}\n\nQuestion: {query}"
answer = llm.generate(prompt)

image = load_image("stop_sign.jpg")  # shape: (224, 224, 3)
edges = conv2d(image, filter=vertical_edge_kernel)
features = cnn.extract_features(image)
prediction = classifier(features)
print(prediction)  # {"stop_sign": 0.97, "yield_sign": 0.02}

distance_cm = ultrasonic.read()
if distance_cm < 15:
    robot.stop()
else:
    robot.move_forward()

def image_callback(msg):
    detections = detect_objects(msg)
    detection_pub.publish(detections)

rospy.Subscriber('/camera/image', Image, image_callback)
detection_pub = rospy.Publisher('/detections', Detections, queue_size=10)

joint_angles = inverse_kinematics(target_xyz=(0.4, 0.1, 0.3))
for angle, limit in zip(joint_angles, joint_limits):
    if abs(angle) > limit:
        raise MotionError('Target unreachable within joint limits')
arm.move_to(joint_angles)

belief = init_particle_filter(n_particles=500)
while robot.running():
    belief = predict(belief, robot.odometry())
    belief = update(belief, robot.sensor_scan(), occupancy_map)
    pose_estimate = belief.weighted_mean()
    occupancy_map = integrate_scan(occupancy_map, robot.sensor_scan(), pose_estimate)

A moody cyberpunk alley at night, neon signs reflecting on wet asphalt,
a lone figure in a translucent raincoat walking away from camera,
volumetric fog, cinematic lighting, shot on 35mm film, shallow depth of field
--ar 16:9 --style raw

# Simplified VLA inference loop running on a humanoid robot
while task_active:
    image = camera.capture()          # current visual observation
    state = robot.proprioception()    # joint angles, velocities, torques

    # single forward pass: perception + language + action in one model
    action_chunk = vla_model.predict(
        image=image,
        instruction="pick up the red mug and place it on the shelf",
        proprio=state,
    )

    for action in action_chunk:       # execute a short horizon of actions
        robot.apply_joint_targets(action)
        if safety_monitor.violation_detected():
            robot.freeze()
            break

Transaction inputs:
  1.2 BTC (from a previous payment you received)

Transaction outputs:
  0.5 BTC -> recipient's address
  0.68 BTC -> change, back to you (minus a small fee)

The 1.2 BTC input is fully "spent" and can never be
reused. It splits into two new outputs, one of which
becomes a new spendable unit (a UTXO) sitting in your
wallet until you spend it again.

# A standard Pay-to-Pubkey-Hash (P2PKH) locking script
OP_DUP OP_HASH160 <pubKeyHash> OP_EQUALVERIFY OP_CHECKSIG

# To spend it, the unlocking script supplies:
<signature> <publicKey>

# The two scripts run together on Bitcoin's stack machine:
# 1. Push signature and public key onto the stack
# 2. Duplicate the public key, hash it, compare to pubKeyHash
# 3. If it matches, verify the signature against the public key
# No loops, no external calls, just a fixed sequence of stack ops.

use bitcoin::{Amount, Transaction, TxIn, TxOut, Sequence, Witness, ScriptBuf};
use bitcoin::transaction::Version;
use bitcoin::locktime::absolute::LockTime;
use bitcoin::{OutPoint, Txid};
use std::str::FromStr;

fn build_transaction() -> Transaction {
    let prev_txid =
        Txid::from_str("f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16")
            .expect("valid txid");

    let input = TxIn {
        previous_output: OutPoint::new(prev_txid, 0),
        script_sig: ScriptBuf::new(),
        sequence: Sequence::ENABLE_RBF_NO_LOCKTIME,
        witness: Witness::new(),
    };

    let recipient_script = ScriptBuf::new_p2wpkh(&"a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2"
        .parse()
        .expect("valid pubkey hash"));

    let output = TxOut {
        value: Amount::from_sat(50_000),
        script_pubkey: recipient_script,
    };

    Transaction {
        version: Version::TWO,
        lock_time: LockTime::ZERO,
        input: vec![input],
        output: vec![output],
    }
}

fn main() {
    let tx = build_transaction();
    println!("txid: {}", tx.compute_txid());
    println!("weight: {} wu", tx.weight());
}

// A minimal smart contract: stores a number, anyone can read it,
// only the owner who deployed it can change it.
contract SimpleStorage {
    uint256 public storedNumber;
    address public owner;

    constructor() {
        owner = msg.sender;
    }

    function setNumber(uint256 newNumber) public {
        require(msg.sender == owner, "Not the owner");
        storedNumber = newNumber;
    }
}

// Vulnerable withdraw pattern vs. the checks-effects-interactions fix
contract VaultVulnerable {
    mapping(address => uint256) public balances;

    function deposit() external payable {
        balances[msg.sender] += msg.value;
    }

    // BAD: sends funds before updating the balance, opens a reentrancy hole
    function withdraw(uint256 amount) external {
        require(balances[msg.sender] >= amount, "insufficient balance");
        (bool sent, ) = msg.sender.call{value: amount}("");
        require(sent, "transfer failed");
        balances[msg.sender] -= amount; // too late, attacker already re-entered
    }
}

contract VaultFixed {
    mapping(address => uint256) public balances;

    function deposit() external payable {
        balances[msg.sender] += msg.value;
    }

    // GOOD: checks-effects-interactions, state is updated before the external call
    function withdraw(uint256 amount) external {
        require(balances[msg.sender] >= amount, "insufficient balance");
        balances[msg.sender] -= amount;
        (bool sent, ) = msg.sender.call{value: amount}("");
        require(sent, "transfer failed");
    }
}

struct UserOperation {
    address sender;          // the smart contract wallet
    uint256 nonce;
    bytes   initCode;        // deploys wallet if it doesn't exist yet
    bytes   callData;        // what the wallet should do
    uint256 callGasLimit;
    uint256 verificationGasLimit;
    uint256 preVerificationGas;
    uint256 maxFeePerGas;
    uint256 maxPriorityFeePerGas;
    bytes   paymasterAndData; // who pays, and how
    bytes   signature;
}

// A bundler collects UserOperations and calls this on the EntryPoint contract
function handleOps(UserOperation[] calldata ops, address payable beneficiary) external;

{
  "messages": [
    { "role": "system", "content": "You are a support agent for Acme Cloud. Always answer in three short bullet points." },
    { "role": "user", "content": "My deploy failed with error E-402, what do I do?" },
    { "role": "assistant", "content": "- E-402 means your build exceeded the memory limit\n- Increase the memory allocation in acme.yaml under 'build.resources'\n- Redeploy, and check the build logs if it fails again" }
  ]
}

PERCEPTION-TO-GRASP PIPELINE

  camera / depth sensor
        |
        v
  segmentation  ->  isolate target object from clutter
        |
        v
  pose estimation  ->  where is it, which way is it facing
        |
        v
  grasp candidate generation  ->  many possible grip points
        |
        v
  grasp scoring  ->  rank by force closure, stability, reachability
        |
        v
  execute + verify  ->  did we actually get it, retry if not