直接座標を指定して多角形を描画する方法です。専用に作られた関数を使えば便利です。
x = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129];
y = [0.259454378238583,0.259004977396962,0.257646462597382,0.255347542836678,0.252054888013056,0.247691376816408,0.242153707189854,0.235309523525177,0.226994434437369,0.217009747805742,0.205122649074174,0.191072284861455,0.174588456510459,0.155435362566237,0.133501896170380,0.108970674541884,0.0825978805926125,0.0560847480074129,0.0323470664907240,0.0152209963651520,0.00826167699292209,0.0133352843308549,0.0303157428089811,0.0577438312133592,0.0933560579153112,0.134267582551197,0.176994138320251,0.217422958749508,0.250993951298588,0.273312061929103,0.281069072787965,0.272869810339360,0.249592983327744,0.214195956568856,0.171126683148973,0.125563882236923,0.0826267061545953,0.0466339906562952,0.0205156088886258,0.00551343119378952,0.00125822862168003,0.00616898130830241,0.0179899795079182,0.0342500755023087,0.0525046964778593,0.0703578373235337,0.0854177491880969,0.0954538882458391,0.0989222364718208,0.0955991112542102,0.0867352694754039,0.0745396741361097,0.0614968721296211,0.0500256242481008,0.0424113398795707,0.0405338833448603,0.0449845180887058,0.0538724523197632,0.0628274347563910,0.0677095008135013,0.0683090987416723,0.0683858044589300,0.0714187762300518,0.0773695216340898,0.0834207273249916,0.0863552160976316,0.0841127582375293,0.0761673964433882,0.0628290861483002,0.0437677999799914,0.0202067670415977,0.00328750578895579,0.00750703913219124,0.0311739750191599,0.0601827782938302,0.0820940124377758,0.0899322129566095,0.0803172011702681,0.0536029160642848,0.0199137431030236,0.00143298355870241,0.00190935381402386,0.00773506804070442,0.0248492393657597,0.0485613752894280,0.0673646905454522,0.0759562105976397,0.0736705499377871,0.0617630821000930,0.0430733315745309,0.0229233897751331,0.00831116873145782,0.00245527785212243,0.00283375992898396,0.0164972942453561,0.0695139639368728,0.152690814024784,0.203228613030337,0.202927817538004,0.171949776373283,0.128475810724997,0.0845918309796656,0.0492236780909716,0.0273908328378636,0.0186624140232090,0.0199040388577439,0.0297448724321350,0.0476328732633558,0.0701238961966722,0.0908670284045613,0.103257848443643,0.102543890856631,0.0871912395829366,0.0603925411687535,0.0308059468028943,0.00961575128100642,0.00371552956888479,0.0115550182933975,0.0266686013138599,0.0435826622119758,0.0595419733708523,0.0732090039101967,0.0835632107952355,0.0895605474880568,0.0900487337318863,0.0838213846009304,0.0703594358600914,0.0529856582073242,0.0438477253138947];
patch([15 30 30 15], [0 0 0.3 0.3], 'cyan', 'EdgeColor', 'none');
hold on
plot(x,y);
