Three-Pentomino Holey Balanced Rectangles

  • Introduction
  • Nomenclature
  • Table
  • Solutions
  • Introduction

    A pentomino is a figure made of five squares joined edge to edge. There are 12 such figures, not distinguishing reflections and rotations. They were first enumerated and studied by Solomon Golomb.

    It has long been known that only four pentominoes can tile rectangles:

    For other rectangles that these pentominoes tile, see Mike Reid's Rectifiable Polyomino Page.

    Rodolfo Kurchan's online magazine Puzzle Fun studied the problem of tiling some rectangle with two different pentominoes, in Issue 19, and revisited the problem in Issue 21. The August 2010 issue of Erich Friedman's Math Magic broadened this problem to use two polyominoes of any size, not necessarily the same.

    In Two-Pentomino Balanced Rectangles I study the related problem of tiling some rectangle with two pentominoes, using the same number of copies of each. Here I study the same problem, allowing one-cell holes in the rectangle. The holes must lie in the interior of the rectangle and must not touch one another.

    Thanks to Jenard Cabilao for suggesting allowing holes in balanced pentomino rectangles.

    Nomenclature

    I use Solomon W. Golomb's original names for the pentominoes:

    Table

    This table shows the area of the smallest rectangle known to be tiled by three pentominoes, using at least one of each, with optional one-cell holes.

    FIL30 FUZ33 IUY30 LWZ63 PVX96
    FIN63 FVW63 IUZ48 LXY32 PVY16
    FIP45 FVX156 IVW32 LXZ98 PVZ30
    FIT48 FVY32 IVX102 LYZ30 PWX108
    FIU30 FVZ60 IVY30 NPT30 PWY30
    FIV30 FWX× IVZ30 NPU15 PWZ30
    FIW63 FWY60 IWX130 NPV30 PXY48
    FIX64 FWZ× IWY30 NPW60 PXZ99
    FIY48 FXY96 IWZ63 NPX64 PYZ30
    FIZ63 FXZ× IXY66 NPY30 TUV32
    FLN30 FYZ60 IXZ117 NPZ30 TUW84
    FLP30 ILN30 IYZ32 NTU48 TUX81
    FLT30 ILP30 LNP30 NTV48 TUY30
    FLU30 ILT32 LNT32 NTW60 TUZ64
    FLV16 ILU30 LNU30 NTX126 TVW32
    FLW30 ILV30 LNV15 NTY30 TVX130
    FLX81 ILW30 LNW30 NTZ64 TVY16
    FLY32 ILX63 LNX63 NUV30 TVZ32
    FLZ60 ILY30 LNY30 NUW63 TWX187
    FNP60 ILZ48 LNZ30 NUX64 TWY30
    FNT64 INP30 LPT32 NUY30 TWZ132
    FNU30 INT30 LPU16 NUZ30 TXY64
    FNV30 INU30 LPV15 NVW30 TXZ×
    FNW× INV30 LPW30 NVX64 TYZ60
    FNX× INW63 LPX48 NVY32 UVW35
    FNY60 INX64 LPY30 NVZ30 UVX117
    FNZ× INY30 LPZ30 NWX× UVY33
    FPT60 INZ60 LTU32 NWY60 UVZ33
    FPU15 IPT30 LTV30 NWZ× UWX336
    FPV30 IPU30 LTW49 NXY63 UWY30
    FPW60 IPV30 LTX30 NXZ× UWZ96
    FPX132 IPW32 LTY15 NYZ60 UXY30
    FPY30 IPX64 LTZ63 PTU30 UXZ162
    FPZ78 IPY30 LUV16 PTV30 UYZ33
    FTU33 IPZ30 LUW30 PTW30 VWX132
    FTV32 ITU32 LUX63 PTX60 VWY33
    FTW120 ITV48 LUY30 PTY30 VWZ33
    FTX× ITW48 LUZ33 PTZ33 VXY66
    FTY30 ITX78 LVW16 PUV15 VXZ132
    FTZ× ITY30 LVX64 PUW48 VYZ30
    FUV48 ITZ63 LVY32 PUX30 WXY96
    FUW30 IUV32 LVZ16 PUY15 WXZ×
    FUX156 IUW63 LWX63 PUZ30 WYZ60
    FUY33 IUX80 LWY30 PVW30 XYZ99

    Solutions

    So far as I know, these solutions have minimal area. They are not necessarily uniquely minimal. For a given area, the number of holes is minimal.

    Area 15

    Area 16

    Area 30

    Area 32

    Area 33

    Area 45

    Area 48

    Area 49

    Area 60

    Area 63

    Area 64

    Area 66

    Area 78

    Area 80

    Area 81

    Area 84

    Area 96

    Area 98

    Area 99

    Area 102

    Area 108

    Area 117

    Area 120

    Area 126

    Area 130

    Area 132

    Area 156

    Area 162

    Area 187

    Area 336

    Last revised 2022-05-22.


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    Col. George Sicherman [ HOME | MAIL ]