On the Exact Algorithmic Extraction of Finite Tesselations Through Prime Extraction of Minimal Representative Forms
Authors: Sushish Baral, Paulo Garcia, Warisa Sritriratanarak
Organizations: Department of Computer Engineering, Chulalongkorn University, Bangkok, Thailand · International School of Engineering, Chulalongkorn University, Bangkok, Thailand
The identification of repeating patterns in discrete grids is rudimentary within symbolic reasoning, algorithm synthesis and structural optimization across diverse computational domains. Although statistical approaches targeting noisy data can approximately recognize patterns, symbolic analysis utilizing deterministic extraction of periodic structures is underdeveloped. This paper aims to fill this gap by employing a hierarchical algorithm that discovers exact tessellations in finite planar grids, addressing the problem where multiple independent patterns may coexist within a hierarchical structure. The proposed method utilizes composite discovery (dual inspection and breadth-first pruning) for identifying rectangular regions with internal repetition, normalization to a minimal representative form, and prime extraction (selective duplication and hierarchical memoization) to account for irregular dimensions and to achieve efficient computation time. We evaluate scalability on grid sizes from 2x2 to 32x32, showing overlap detection on simple repeating tiles exhibits processing time under 1ms, while complex patterns which require exhaustive search and systematic exploration shows exponential growth. This algorithm provides deterministic behavior for exact, axis-aligned, rectangular tessellations, addressing a critical gap in symbolic grid analysis techniques, applicable to puzzle solving reasoning tasks and identification of exact repeating structures in discrete symbolic domains.
Figures & tables
Figure 1: ARC tasks; reproduced from https://arcprize.org/play?task=0a938d79
Figure 2: Example grid and identified tesselations, with connections to respective tiles.
Figure 3: BFS pruning tree for composite discovery showing node status by color: green (continue), pink/red (tessellation found), orange (duplicate), light blue (near minimum), dark red (empty), purple (prime). Three composites discovered at bottom.
Figure 4: Normalization process reducing three composites (Tc, pink) to minimal forms (Tc’, purple) through iterative row/column halving with duplication.
Figure 5: Prime extraction BFS tree with overlap detection and normalization. Colors indicate: purple (primes), orange (duplicates), dark red (empty). Bottom panel shows level-wise organization (Levels 1-4).
Figure 6: Primes organized by BFS discovery level for dual-strategy MDL assembly.
Test Case
Grid
Composites
Discovery
Normalization
Prime + Puzzle
Total
Size
Found / Processed
Solving
Band-in-blanks
6×6
1 / 1
0.17
0.04
0.16
0.64
Mixed-noise
6×8
14 / 4
3.91
0.17
2.90
8.43
Simple-pattern
4×4
1 / 1
0.06
0.03
0.99
1.48
Table 1: Timing Analysis (milliseconds)
Figure 7: Time complexity for composite discovery, prime extraction and total time taken.
Test Case
Composites
Primes
Optimal Solutions
Found / Processed / Skipped
Found
(Cumulative Strategy)
Band-in-blanks
1 / 1 / 0
1
1 (1 step)
Mixed-noise
14 / 4 / 10
20
3 (2 steps)
Simple-pattern
1 / 1 / 0
4
2 (2 steps)
Table 2: Decomposition Statistics Summary
Test Case
Composite
Size
Prime Tiles (organized by BFS Level)
ID
Band-in-blanks
#1
2×1
Prime is the composite itself: 1/2 ( 2×1 )
Mixed-noise
#1
2×4
19 primes across multiple levels including 12-- ( 1×4 ), 3-4- ( 1×4 ), 12 ( 1×2 ), 1/3 ( 2×1 ), and others
#7
3×1
1 prime: -/Q ( 2×1 )
#2–#6, #8–#11, #13
Various
Skipped (already discovered as primes of Composite #1)
#12, #14
2×1
Processed but yielded 0 primes (minimal size)
Table 3: Composites and Extracted Primes
Test Case
Strategy
Solutions (tile placements required)
Band-in-blanks
Cumulative
Solution uses the composite itself: 1/2 (1 placement)
Level 1
Same as cumulative
Mixed-noise
Cumulative
3 solutions, each requiring 2 placements: (1) 12-- and 3-4- ; (2) 12/3- and --/4- ; (3) 1/3 and 2--/--4-
Level 1
1 solution using large tiles (2 placements)
Level 2
1 solution using medium tiles (2 placements)
Simple-pattern
Cumulative
2 solutions, each requiring 2 placements: (1) 10 and 0/2 ; (2) 1/0 and 02
Table 4: Optimal Solutions from Cumulative and Per-Level Strategies
Figure 8: Scalability analysis on log-log scale: overlap patterns remain constant while pruning patterns grow exponentially.