Visual sequence showing the progression of a pattern formed by yellow squares, starting with a single square and building upward and outward in a step-like formation.

Let’s look at the pattern in the shapes.

We are given 4 figures, each made of yellow squares. Let’s count how many squares are in each figure:

- Figure 1: Just 1 square → total = 1
- Figure 2: A base of 3 squares + 1 on top → total = 4
- Figure 3: A base of 5 squares + 2 stacked on the middle one → total = 7
- Figure 4: A base of 7 squares + 3 stacked on the middle one → total = 10

Now let’s list the totals:

Figure 1 → 1
Figure 2 → 4
Figure 3 → 7
Figure 4 → 10

Look at how the numbers grow:

From 1 to 4 → +3
From 4 to 7 → +3
From 7 to 10 → +3

So every time we go to the next figure, we add 3 more squares.

That means this is an arithmetic sequence where each term increases by 3.

We can write a rule for the number of squares in figure n:

Start with figure 1: 1
Then each next figure adds 3.

So for figure n:
Number of squares = 1 + (n - 1) × 3

Let’s test it:

For n=1: 1 + (0)×3 = 1 ✔
For n=2: 1 + (1)×3 = 4 ✔
For n=3: 1 + (2)×3 = 7 ✔
For n=4: 1 + (3)×3 = 10 ✔

Perfect!

Now, if the question is asking for the number of squares in figure 5 (since it shows up to 4 and likely wants the next), then:

Figure 5: 1 + (5 - 1) × 3 = 1 + 4×3 = 1 + 12 = 13

But wait — let’s double-check by building it visually.

In figure 4: base has 7 squares, tower has 3 high.

Pattern for base:
Fig 1: base = 1
Fig 2: base = 3
Fig 3: base = 5
Fig 4: base = 7
→ So base = 2n - 1

Tower height:
Fig 1: tower = 0? But actually fig 1 is just 1 square — maybe tower starts at fig 2.

Actually, looking again:

Fig 1: only 1 square — no separate tower. Maybe think of it as tower height = 0? But then total would be base only.

Alternatively, notice:

Total squares = base + tower

Base: always odd numbers starting at 1: 1, 3, 5, 7 → so for figure n, base = 2n - 1

Tower: for fig 1, tower = 0? But total is 1. If base is 1, tower must be 0.

Fig 2: base=3, tower=1 → total=4
Fig 3: base=5, tower=2 → total=7
Fig 4: base=7, tower=3 → total=10

So tower height = n - 1

Thus total = base + tower = (2n - 1) + (n - 1) = 3n - 2

Check:

n=1: 3(1)-2 = 1 ✔
n=2: 6-2=4 ✔
n=3: 9-2=7 ✔
n=4: 12-2=10 ✔

Same result as before! Because 3n - 2 = 1 + (n-1)*3 → yes, same formula.

So for figure 5: 3×5 - 2 = 15 - 2 = 13

Or using the other way: 1 + (5-1)*3 = 13

Either way, answer is 13.

Final Answer:
13