# Drawing a rectangle with Matplotlib

I’m writing a python function to draw a simple rectangle, the vertex points are parameters. Well, this does not work correctly and I can’t seem to find out why its plotting all over the place. EDIT: as for my imports. So sp is sympy. As for the expected result to draw a rectangle of course.

```%matplotlib inline
import sympy as sp
import numpy as np
import matplotlib.pyplot as plt
import math

def draw_rectangle(P1,P2,P3,P4):
p1, p2, p3, p4 = sp.Point(P1, P1), sp.Point(P2, P2), sp.Point(P3, P3),
sp.Point(P4, P4)
plt.plot(p1,p2)
plt.plot(p2,p3)
plt.plot(p3,p4)
plt.plot(p4,p1)

P1=[20,30]
P2=[40,30]
P3=[40,60]
P4=[20,60]
draw_rectangle(P1,P2,P3,P4)

```

Actual Outcome with this code The delivery of the x-y coordinates is mixed up in your code. `p1` is still in the same form as `P1`, i.e., an x-y pair. But matplotlib `plt.plot()` expects a list of x-values followed by a list of y-values. Hence, this misunderstanding – matplotlib interpreted in `plt.plot(p1,p2)` `p1` as two x-values and `p2` as two y-values. So, we have to chain the x- and the y-values together before plotting.

```import sympy as sp
import matplotlib.pyplot as plt

def draw_rectangle(P1,P2,P3,P4):
p1, p2 = sp.Point(P1, P1), sp.Point(P2, P2)
p3, p4 = sp.Point(P3, P3), sp.Point(P4, P4)
plt.plot(*zip(p1,p2))
plt.plot(*zip(p2,p3))
plt.plot(*zip(p3,p4))
plt.plot(*zip(p4,p1))
#or alternatively
#plt.plot(*zip(p1, p2, p3, p4, p1))

P1=[20,30]
P2=[40,30]
P3=[40,60]
P4=[20,60]

draw_rectangle(P1,P2,P3,P4)
plt.show()
```

Sample output: However, it remains unclear why you converted your data into `sympy` points before plotting. You could have directly used `P1`, `P2`,…, but maybe this is required for some other program parts we are not aware of. Or you actually wanted to use another `sympy` function, not `sp.point`, but I don’t speak fluent `sympy`, so cannot comment on that.

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