A unit cube is cut twice to form three triangular prisms, two of which are congruent, as shown in Figure 1. The cube is then cut in the same manner along the dashed lines shown in Figure 2. This creates nine pieces. What is the volume of the piece that contains vertex $ W$?
[asy]import three;
size(200);
defaultpen(linewidth(.8pt)+fontsize(10pt));

currentprojection=oblique;
path3 p1=(0,2,2)--(0,2,0)--(2,2,0)--(2,2,2)--(0,2,2)--(0,0,2)--(2,0,2)--(2,2,2);
path3 p2=(2,2,0)--(2,0,0)--(2,0,2);
path3 p3=(0,0,2)--(0,2,1)--(2,2,1)--(2,0,2);
path3 p4=(2,2,1)--(2,0,0);
pen finedashed=linetype("4 4");

draw(p1^^p2^^p3^^p4);
draw(shift((4,0,0))*p1);
draw(shift((4,0,0))*p2);
draw(shift((4,0,0))*p3);
draw(shift((4,0,0))*p4);
draw((4,0,2)--(5,2,2)--(6,0,2),finedashed);
draw((5,2,2)--(5,2,0)--(6,0,0),finedashed);

label("$W$",(3,0,2));
draw((2.7,.3,2)--(2.1,1.9,2),linewidth(.6pt));
draw((3.4,.3,2)--(5.9,1.9,2),linewidth(.6pt));
label("Figure 1",(1,-0.5,2));
label("Figure 2",(5,-0.5,2));[/asy]$ \textbf{(A)}\ \frac {1}{12}\qquad \textbf{(B)}\ \frac {1}{9}\qquad \textbf{(C)}\ \frac {1}{8}\qquad \textbf{(D)}\ \frac {1}{6}\qquad \textbf{(E)}\ \frac {1}{4}$
1. **Understanding the Problem:**
   - We start with a unit cube, which has a volume of \(1 \, \text{unit}^3\).
   - The cube is cut twice to form three triangular prisms, two of which are congruent.
   - The cube is then cut again along the dashed lines shown in Figure 2, creating nine pieces.
   - We need to find the volume of the piece that contains vertex \(W\).

2. **Analyzing the Cuts:**
   - The first set of cuts divides the cube into three triangular prisms.
   - The second set of cuts further divides these prisms into smaller pieces.

3. **Volume Calculation:**
   - The piece containing vertex \(W\) is a triangular prism with a square base.
   - The side length of the square base is \(\frac{1}{2}\) (since the unit cube is divided into smaller sections).
   - The height of the prism is \(1\) (the height of the original unit cube).

4. **Volume of the Triangular Prism:**
   - The base area of the triangular prism is calculated as:
     \[
     \text{Base Area} = \frac{1}{2} \times \left(\frac{1}{2} \times \frac{1}{2}\right) = \frac{1}{2} \times \frac{1}{4} = \frac{1}{8}
     \]
   - The volume of the triangular prism is then:
     \[
     V = \text{Base Area} \times \text{Height} = \frac{1}{8} \times 1 = \frac{1}{8}
     \]

5. **Verification:**
   - Since the cube is divided into nine equal pieces, each piece should have a volume of:
     \[
     \frac{1}{9} \, \text{unit}^3
     \]
   - However, the piece containing vertex \(W\) is not one of these equal pieces. It is a triangular prism with a different volume.

6. **Correct Volume Calculation:**
   - The correct volume of the piece containing vertex \(W\) is:
     \[
     V = \frac{1}{3} \times 1 \times \left(\frac{1}{2} \times \frac{1}{2}\right) = \frac{1}{3} \times 1 \times \frac{1}{4} = \frac{1}{12}
     \]

The final answer is \(\boxed{\frac{1}{12}}\)