Concept:
When an object is divided vertically through its centre, a vertically symmetrical figure will have identical left and right halves. The odd figure is the one that does \emph{not} satisfy this condition.
Step-by-step analysis: Figure 1:
The two small squares with diagonal crosses are placed diagonally.
After vertical division, the left and right halves do not match.
Hence, it is not vertically symmetrical.
Figure 2:
The crossed squares at the bottom are arranged symmetrically about the vertical centre line.
Figure 3:
The two crossed squares at the top are mirror images across the vertical centre.
Figure 4:
The stacked crossed squares are centrally placed and remain identical on both sides after division.
Conclusion:
Only Figure 1 fails the vertical symmetry test. Hence, it is the odd one out.
Final Answer: \(\boxed{\text{Figure 1}}\)
