Tab 0:
--unknown ocean
--markus

--init
tile=0
found=0
fb=0
v=0
pos=0
mode=0
state=0
r=0
blueprint=0
p = {
  x=16,
  y=16,
  celx=16/8,
  cely=16/8
}

slct={
  n=0,
  x=8
}

mouse={
  x=0,
  y=0,
  b=0
}
pattern = {}

Tab 1:
--update
music(0)
function _update()
  p.celx = p.x/8
  p.cely = p.y/8
  if r==0 then
    if state==0 then
      update_menu()
    elseif state==1 then
      update_blueprnt()
    elseif state==2 then
      update_game()
    end
  end
  if state==3 then
    update_win()
  end
  mouse_coord()
  if r==1 then end_update() end
end

function update_menu()
  if btnp(1) or mouse.b==1then
    random()
    state=1
    music(1)
  end
end

function update_game()
  end_check()
  if btnp(4) then
    if mode!= 2 then
      mode+=1
    else mode=0 end
  end
  if mode==0 then update_move()
  elseif mode==1 then update_build()
  else update_place() end
  --move hotbar
  slct.x = slct.n*8
end

function update_build()
  if btnp(1) then
    if slct.n!=4 then
      slct.n+=1
      else slct.n=0 end
    elseif btnp(0) then
      if slct.n!=0 then
        slct.n-=1
      else slct.n=4 end
  end
end

function update_move()
  if btnp(5) then
    r=1
    find_pattern()
    if found==1 then
      found=0
      state = 3
    end
  end
  if btnp(0) and fget(mget(p.celx-1,p.cely),0)==false then
    p.x-=8
    sfx(4)
  elseif btnp(1) and fget(mget(p.celx+1,p.cely),0)==false then
    p.x+=8
    sfx(4)
  elseif btnp(2) and fget(mget(p.celx,p.cely-1),0)==false then
    p.y-=8
    sfx(4)
  elseif btnp(3) and fget(mget(p.celx,p.cely+1),0)==false then
    p.y+=8
    sfx(4)
  end
end

function update_place()
  if btnp(0) then pos=0
  elseif btnp(1) then pos=1
  elseif btnp(2) then pos=2
  elseif btnp(3) then pos=3 end

    if btnp(5) or mouse.b==1 then
      fb=3
    if pos==0 then
      mset(p.celx-1,p.cely,slct.n+3)
      sfx(3)
    elseif pos==1 then
      mset(p.celx+1,p.cely,slct.n+3)
      sfx(3)
    elseif pos==2 then
      mset(p.celx,p.cely-1,slct.n+3)
      sfx(3)
    elseif pos==3 then
      mset(p.celx,p.cely+1,slct.n+3)
      sfx(3)
    end
  end
end

function mouse_coord()
  poke(0x5f2d, 1)
  mouse.x = stat(32)
  mouse.y = stat(33)
  mouse.b = stat(34)
end

function end_check()
  if fget(mget(p.celx-1,p.cely),0)and
    fget(mget(p.celx+1,p.cely),0)and
    fget(mget(p.celx,p.cely-1),0)and
    fget(mget(p.celx,p.cely+1),0)then
    r=1
  end
end

function end_update()
  if btnp(1) then
    for i=0,4 do
      for j=0,5 do
	mset(i,j,2)
      end
    end
    for i=0,16 do
      mset(i,15,18)
    end
    p.x=16
    p.y=16
    mode=0
    pos=0
    r=0
    slct.n=0
    slct.x=8
    mset(0,0,21)
    mset(1,0,22)
    mset(2,0,19)
    mset(3,0,20)
    mset(4,0,35)
  end
end

function random()
  pattern={}
  for j=17,19 do
    for i=17,19 do
      tile=(flr(rnd(6))+3)
      if tile == 8 then
	tile=2
      end
      mset(i,j,tile)
      add(pattern,mget(i,j))
    end
  end
end

function update_blueprnt()
  if btnp(1) then state=2 end
end

function update_win()
  if v==1 then
    if btnp(1) then
      state = 0
      v=0
    end
  end
end

function find_pattern()
  for y=1,4 do
    for x=0,3 do
      if mget(x,y)==pattern[1] then
        if mget(x+1,y)==pattern[2] then
	  if mget(x+2,y)==pattern[3] then
	    if mget(x,y+1)==pattern[4] then
	      if mget(x+1,y+1)==pattern[5] then
		if mget(x+2,y+1)==pattern[6] then
		  if mget(x,y+2)==pattern[7] then
		    if mget(x+1,y+2)==pattern[8] then
		      if mget(x+2,y+2)==pattern[9] then
			found=1
		      end
		    end
		  end
		end
	      end
	    end
	  end
        end
      end
    end
  end
end

Tab 2:
--draw
function _draw()
  if state==0 then
    draw_menu()
  elseif state==1 then
    draw_blueprnt()
  elseif state==2 then
    draw_game()
  elseif state==3 then
    draw_game()
  end
  spr(9,mouse.x,mouse.y)
end

function draw_menu()
  cls()
  rectfill(0,0,128,128,1)
  print("unknown ocean",40,20,0)
  print("press ➡️ or left click to start",3,70)
end

function draw_game()
  cls()
  if fb==1 then
    feedback()
  end
  if fb !=0 then
    fb-=1
  end
  map(0,0,0,0,5,6)
  spr(17,slct.x,0)
  spr(1,p.x,p.y)
  if r==0 then
    draw_dark()
    if mode==0 then
      print("move",105,4,7)
    elseif mode==1 then
      print("select",105,4,7)
    else print("build",105,4,7) end
  end
  --place block
  if mode==2 then
    if r==0 then
      if pos==0 then
        spr(17,p.x-8,p.y)
      elseif pos==1 then
        spr(17,p.x+8,p.y)
      elseif pos==2 then
        spr(17,p.x,p.y-8)
      elseif pos==3 then
        spr(17,p.x,p.y+8)
      end
    end
  end

  if state==3 and btnp(1)then
    v=1
  end
  if v==1 then draw_win() end
end

function draw_dark()
  rectfill(0,8,39,47,5)
end

function draw_blueprnt()
  cls()
  rectfill(0,0,128,128,1)
  rectfill(46,46,77,77,2)
  map(17,17,50,50,3,3)
end

function draw_win()
  rectfill(0,0,128,128,1)
  print("you win!",50,40,0)
end

function feedback()
  rectfill(0,0,42,50,7)
end