Knowledge

The spider and the fly problem

Source 📝

20: 248:. Depending on the dimensions of the cuboid, and on the initial positions of the spider and fly, one or another of these paths, or of four other paths, may be the optimal solution. However, there is no rectangular cuboid, and two points on the cuboid, for which the shortest path passes through all six faces of the cuboid. 67:
A naive solution is for the spider to remain horizontally centred, and crawl up to the ceiling, across it and down to the fly, giving a distance of 42 feet. Instead, the shortest path, 40 feet long, spirals around five of the six faces of the cuboid. Alternatively, it can be described by unfolding
58:
room 30 feet long, 12 feet wide and 12 feet high contains a spider and a fly. The spider is 1 foot below the ceiling and horizontally centred on one 12′×12′ wall. The fly is 1 foot above the floor and horizontally centred on the opposite wall. The problem is to find the minimum
72:
and finding a shortest path (a line segment) on the resulting unfolded system of six rectangles in the plane. Different nets produce different segments with different lengths, and the question becomes one of finding a net whose segment length is minimum. Another path, of intermediate length
259:
to the wall to lower itself to the floor, and crawling 30 feet across it and 1 foot up the opposite wall, giving a crawl distance of 31 feet. Similarly, it can climb to the ceiling, cross it, then attach the silk to lower itself 11 feet, also a 31-foot crawl.
198: 101: 246: 569: 395: 574: 411:
Miller, S. Michael; Schaefer, Edward F. (Spring 2015). "The distance from a point to its opposite along the surface of a box".
321: 461:; Ito, Hiro; Katayama, Yuta; Murayama, Wataru; Uno, Yushi (2022). "Geodesic paths passing through all faces on a polyhedron". 129: 59:
distance the spider must crawl along the walls, ceiling and/or floor to reach the fly, which remains stationary.
76: 31: 292: 413: 23:
Isometric projection and net of naive (1) and optimal (2) solutions of the spider and the fly problem
511: 462: 528: 432: 422: 338: 509:(June 1958). "About Henry Ernest Dudeney, a brilliant creator of puzzles". Mathematical Games. 203: 482: 391: 296: 390:. Classroom Resource Materials. Vol. 28. American Mathematical Society. pp. 45–46. 383: 520: 464:
24th Japan Conference on Discrete and Computational Geometry, Graphs, and Games (JCDCG 2022)
364: 330: 252: 69: 547: 356: 485: 524: 506: 458: 454: 281: 19: 563: 342: 288: 269: 256: 43: 549:
Hurwitz's Complex Continued Fractions: A Historical Approach and Modern Perspectives
334: 450: 552:(Doctoral dissertation). Julius-Maximilians-Universität Würzburg. pp. 36–41. 368: 319:
Mellinger, Keith E.; Viglione, Raymond (March 2012). "The spider and the fly".
255:
solution, beyond the stated rules of the puzzle, involves the spider attaching
490: 35: 532: 436: 55: 39: 34:
problem with an unintuitive solution, asking for a shortest path or
427: 359:; Chinn, William G. (1985). "Chapter 16: The Spider and the Fly". 18: 388:
Math Made Visual: Creating Images for Understanding Mathematics
291:
in his diary in 1908. Hurwitz stated that he heard it from
103:, crosses diagonally through four faces instead of five. 54:
In the typical version of the puzzle, an otherwise empty
206: 132: 79: 240: 192: 95: 193:{\displaystyle {\sqrt {(w+h)^{2}+(b+l+a)^{2}}}} 284:calls it "Dudeney's best-known brain-teaser". 126:above the floor, length of the spiral path is 8: 546:Oswald, Nicola (2014). "Spider meets Fly?". 122:below the ceiling, and the fly a distance 96:{\displaystyle {\sqrt {1658}}\approx 40.7} 426: 382:Alsina, Claudi; Nelsen, Roger B. (2006). 287:A version of the problem was recorded by 233: 219: 205: 182: 151: 133: 131: 80: 78: 363:. Boston: Birkhäuser. pp. 117–122. 308: 38:between two points on the surface of a 7: 314: 312: 268:The problem was originally posed by 200:while the naive solution has length 525:10.1038/scientificamerican0658-108 14: 276:on 14 June 1903 and collected in 295:, who in turn had heard it from 335:10.4169/college.math.j.43.2.169 322:The College Mathematics Journal 234: 220: 179: 160: 148: 135: 28:The spider and the fly problem 16:Recreational geodesics problem 1: 42:. It was originally posed by 384:"9.4 The spider and the fly" 369:10.1007/978-1-4615-8519-0_16 591: 272:in the English newspaper 241:{\displaystyle l+h-|b-a|} 570:Recreational mathematics 486:"Spider and Fly Problem" 118:, the spider a distance 32:recreational mathematics 575:Geodesic (mathematics) 293:L. Gustave du Pasquier 278:The Canterbury Puzzles 242: 194: 97: 24: 414:Pi Mu Epsilon Journal 243: 195: 106:For a room of length 98: 22: 204: 130: 77: 512:Scientific American 361:3.1416 And All That 483:Weisstein, Eric W. 455:Demaine, Martin L. 238: 190: 93: 68:the cuboid into a 25: 470:. pp. 58–59. 297:Richard von Mises 188: 85: 582: 554: 553: 543: 537: 536: 503: 497: 496: 495: 478: 472: 471: 469: 451:Demaine, Erik D. 447: 441: 440: 430: 408: 402: 401: 379: 373: 372: 357:Davis, Philip J. 353: 347: 346: 316: 253:lateral thinking 247: 245: 244: 239: 237: 223: 199: 197: 196: 191: 189: 187: 186: 156: 155: 134: 102: 100: 99: 94: 86: 81: 590: 589: 585: 584: 583: 581: 580: 579: 560: 559: 558: 557: 545: 544: 540: 507:Gardner, Martin 505: 504: 500: 481: 480: 479: 475: 467: 459:Eppstein, David 449: 448: 444: 410: 409: 405: 398: 381: 380: 376: 355: 354: 350: 318: 317: 310: 305: 274:Weekly Dispatch 266: 202: 201: 178: 147: 128: 127: 75: 74: 65: 52: 17: 12: 11: 5: 588: 586: 578: 577: 572: 562: 561: 556: 555: 538: 519:(6): 108–114. 498: 473: 442: 421:(2): 143–154. 403: 396: 374: 348: 329:(2): 169–172. 307: 306: 304: 301: 282:Martin Gardner 265: 262: 236: 232: 229: 226: 222: 218: 215: 212: 209: 185: 181: 177: 174: 171: 168: 165: 162: 159: 154: 150: 146: 143: 140: 137: 92: 89: 84: 64: 61: 51: 48: 15: 13: 10: 9: 6: 4: 3: 2: 587: 576: 573: 571: 568: 567: 565: 551: 550: 542: 539: 534: 530: 526: 522: 518: 514: 513: 508: 502: 499: 493: 492: 487: 484: 477: 474: 466: 465: 460: 456: 452: 446: 443: 438: 434: 429: 424: 420: 416: 415: 407: 404: 399: 397:9781614441007 393: 389: 385: 378: 375: 370: 366: 362: 358: 352: 349: 344: 340: 336: 332: 328: 324: 323: 315: 313: 309: 302: 300: 298: 294: 290: 289:Adolf Hurwitz 285: 283: 279: 275: 271: 270:Henry Dudeney 263: 261: 258: 257:dragline silk 254: 249: 230: 227: 224: 216: 213: 210: 207: 183: 175: 172: 169: 166: 163: 157: 152: 144: 141: 138: 125: 121: 117: 113: 109: 104: 90: 87: 82: 71: 62: 60: 57: 49: 47: 45: 44:Henry Dudeney 41: 37: 33: 29: 21: 548: 541: 516: 510: 501: 489: 476: 463: 445: 418: 412: 406: 387: 377: 360: 351: 326: 320: 286: 277: 273: 267: 251:A different 250: 123: 119: 115: 111: 107: 105: 66: 53: 27: 26: 114:and height 564:Categories 428:1502.01036 303:References 491:MathWorld 343:117839570 228:− 217:− 88:≈ 63:Solutions 533:24941034 437:24340739 280:(1907). 110:, width 36:geodesic 264:History 50:Problem 531:  435:  394:  341:  56:cuboid 40:cuboid 529:JSTOR 468:(PDF) 433:JSTOR 423:arXiv 339:S2CID 30:is a 392:ISBN 91:40.7 83:1658 521:doi 517:198 365:doi 331:doi 70:net 566:: 527:. 515:. 488:. 457:; 453:; 431:. 419:14 417:. 386:. 337:. 327:43 325:. 311:^ 299:. 46:. 535:. 523:: 494:. 439:. 425:: 400:. 371:. 367:: 345:. 333:: 235:| 231:a 225:b 221:| 214:h 211:+ 208:l 184:2 180:) 176:a 173:+ 170:l 167:+ 164:b 161:( 158:+ 153:2 149:) 145:h 142:+ 139:w 136:( 124:a 120:b 116:h 112:w 108:l

Index


recreational mathematics
geodesic
cuboid
Henry Dudeney
cuboid
net
lateral thinking
dragline silk
Henry Dudeney
Martin Gardner
Adolf Hurwitz
L. Gustave du Pasquier
Richard von Mises


The College Mathematics Journal
doi
10.4169/college.math.j.43.2.169
S2CID
117839570
Davis, Philip J.
doi
10.1007/978-1-4615-8519-0_16
"9.4 The spider and the fly"
ISBN
9781614441007
Pi Mu Epsilon Journal
arXiv
1502.01036

Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.