Объясните что за что отвечает в этом коде, а то ничего не понятно :(Uses graphABC,ABCObjects;vari,xhead,yhead,z,appleX,appleY:integer;head:CircleABC;snake:array[1. . 4] of CircleABC;apple:circleABC;score:TextABC;procedure keyDown(key:integer);beginif(key = vk_Right) then z := 1;if(key = vk_Left) then z := 2;if(key = vk_Up) then z := 3;if(key = vk_Down) then z := 4;end;beginfor i:=0 to 6 dobeginline(0,i*80,windowWidth,i*80);end;for i:=0 to 8 dobeginline(i*80,0,i*80,windowHeight);end;xhead := 3*80 - 40;yhead := 2*80 - 40;appleX := 6*80 - 40;appleY := 3*80 - 40;apple := CircleABC. Create(appleX,appleY,40,clRed);head := CircleABC. Create(xhead,yhead,40,clBlue);for i:=1 to 4 dobeginsnake[i] := CircleABC. Create(xhead,yhead+80*i,40,clBlue);end;score := TextABC. Create(5,0,80,'0',clGreen);while(true) dobeginonKeyDown := keyDown;if(z <> 0) thenbeginfor i:=4 downto 2 dobeginsnake[i]. MoveTo(snake[i-1]. Position. X,snake[i-1]. Position. Y);end;snake[1]. MoveTo(xhead-40,yhead-40);end;if(z = 1) then xhead := xhead + 80else if (z = 2) then xhead := xhead - 80else if (z = 3) then yhead := yhead - 80else if (z = 4) then yhead := yhead + 80;if(xhead > windowWidth) then xhead := 40;if(xhead < 0) then xhead := windowWidth - 40;if(yhead > windowHeight) then yhead := 40;if(yhead < 0) then yhead := windowHeight - 40;if((xHead = appleX) and (yHead = appleY)) thenbeginappleX := random(1,8)*80 - 40;appleY := random(1,6)*80 - 40;apple. MoveTo(appleX-40,appleY - 40);score. Text := ((score. Text). ToInteger + 1). ToString();end;head. MoveTo(xhead-40,yhead - 40);sleep(200);end;end.