import tkinter as tk
x = 0
y = 0
array = [[11,12,13,14],[21,22,23,24],[31,32,33,34],[41,42,43,44]]
running = True
def start():
global x, y, running
x = y = 0
running = True
output()
def skip():
global x, y
x +=1
y = 0
def stop():
global running
running = False
def output():
global x, y, running
try:
print(array[x][y])
except IndexError as e:
if x >= len(array):
#Run out of lists
running = False
elif y >= len(array[x]):
y = 0
x += 1
else:
raise e
y += 1
if running:
root.after(1000, output)
root = tk.Tk()
btnStart = tk.Button(root,text="Start",command=start)
btnSkip = tk.Button(root,text="Skip",command=skip)
btnStop = tk.Button(root,text="Stop",command=stop)
btnStart.grid()
btnSkip.grid()
btnStop.grid()
root.mainloop()