Make target dice sequence a ping-pong triangle wave

[radiantnode]

Problem

The round target cycled 1→2→3→4→5→6→1, jumping abruptly from 6 straight back down to 1 each time it wrapped. The progression should instead climb and descend smoothly — 1,2,3,4,5,6,5,4,3,2,1,2,3,4,5,6,….

Why the value-based approach couldn't work

A ping-pong sequence can't be derived from the current target value alone: when the target is 3, the next value could be 2 (descending) or 4 (ascending). The value carries no direction.

Fix

Replaced next_target(t) with target_for_round(round_num), which reads direction off round_num — a monotonic counter already tracked and incremented every round — as a triangle wave:

def target_for_round(round_num: int) -> int:
    m = (round_num - 1) % 10
    return m + 1 if m <= 5 else 11 - m

Period 10. Round 1 maps to target 1, matching the value set at game creation, so the invariant holds from the first round. advance_round now calls target_for_round(old_round + 1).

Changes

• server/game.py — replaced next_target with target_for_round
• server/broadcast.py — advance_round uses target_for_round(old_round + 1)
• CLAUDE.md — updated the round-lifecycle description

Verification

Confirmed the generated sequence matches 1,2,3,4,5,6,5,4,3,2,1,2,… across 22 rounds and that both modules parse. No existing tests referenced the old function.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Ug1kqfq8hC7G8PstttbzY8

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Generated by Claude Code