diff --git a/Book4_Ch07_Python_Codes/Streamlit_Bk4_Ch7_01.py b/Book4_Ch07_Python_Codes/Streamlit_Bk4_Ch7_01.py
deleted file mode 100644
index 466e95a..0000000
--- a/Book4_Ch07_Python_Codes/Streamlit_Bk4_Ch7_01.py
+++ /dev/null
@@ -1,116 +0,0 @@
-
-###############
-# Authored by Weisheng Jiang
-# Book 4  |  From Basic Arithmetic to Machine Learning
-# Published and copyrighted by Tsinghua University Press
-# Beijing, China, 2022
-###############
-
-import plotly.graph_objects as go
-import numpy as np
-from plotly.subplots import make_subplots
-import streamlit as st
-
-
-def bmatrix(a):
-    """Returns a LaTeX bmatrix
-
-    :a: numpy array
-    :returns: LaTeX bmatrix as a string
-    """
-    if len(a.shape) > 2:
-        raise ValueError('bmatrix can at most display two dimensions')
-    lines = str(a).replace('[', '').replace(']', '').splitlines()
-    rv = [r'\begin{bmatrix}']
-    rv += ['  ' + ' & '.join(l.split()) + r'\\' for l in lines]
-    rv +=  [r'\end{bmatrix}']
-    return '\n'.join(rv)
-
-n = m = 20
-
-fig = make_subplots(rows=1, cols=2, horizontal_spacing=0.035)
-
-xv = []
-yv = [] 
-
-for k in range(-n, n+1):
-    xv.extend([k, k, np.nan])
-    yv.extend([-m, m, np.nan])
-lw= 1 #line_width
-fig.add_trace(go.Scatter(x=xv, y=yv, mode="lines", line_width=lw,
-                         line_color = 'red'), 1, 1)
-#set up  the lists  of  horizontal line x and y-end coordinates
-
-xh=[]
-yh=[]
-for k in range(-m, m+1):
-    xh.extend([-m, m, np.nan])
-    yh.extend([k, k, np.nan])
-    fig.add_trace(go.Scatter(x=xh, y=yh, mode="lines", line_width=lw,
-                             line_color = 'blue'), 1, 1)
-
-
-with st.sidebar:
-    
-    st.latex(r'''
-             A = \begin{bmatrix}
-    a & b\\
-    c & d
-    \end{bmatrix}''')
-    
-    a = st.slider('a',-2.0, 2.0, step = 0.1, value = 1.0)
-    b = st.slider('b',-2.0, 2.0, step = 0.1, value = 0.0)  
-    c = st.slider('c',-2.0, 2.0, step = 0.1, value = 0.0)  
-    d = st.slider('c',-2.0, 2.0, step = 0.1, value = 1.0) 
-
-theta = np.pi/6
-A = np.array([[a, b], 
-              [c, d]], dtype=float)
-
-#get only the coordinates from -3 to 3
-# X = np.array(xv[6:-6])
-# Y = np.array(yv[6:-6])
-
-X = np.array(xv)
-Y = np.array(yv)
-
-# transform by T the vector of coordinates [x, y]^T where the vector runs over the columns of np.stack((X, Y))
-Txvyv = A@np.stack((X, Y)) #transform by T the vertical lines
-
-# X = np.array(xh[6:-6])
-# Y = np.array(yh[6:-6])
-
-X = np.array(xh)
-Y = np.array(yh)
-
-Txhyh = A@np.stack((X, Y))# #transform by T the horizontal lines
-
-st.latex(bmatrix(A))
-
-a1 = A[:,0].reshape((-1, 1))
-a2 = A[:,1].reshape((-1, 1))
-
-st.latex(r'''
-         a_1 = Ae_1 = ''' + bmatrix(A) + 
-         'e_1 = ' + bmatrix(a1)
-         )
-
-st.latex(r'''
-         a_2 = Ae_2 = ''' + bmatrix(A) + 
-         'e_2 = ' + bmatrix(a2)
-         )
-
-
-fig.add_trace(go.Scatter(x=Txvyv[0], y=Txvyv[1], 
-                         mode="lines", line_width=lw,
-                         line_color = 'red'), 1, 2)
-
-fig.add_trace(go.Scatter(x=Txhyh[0], y=Txhyh[1], 
-                         mode="lines", line_width=lw,
-                         line_color = 'blue'), 1, 2)
-fig.update_xaxes(range=[-4, 4])
-fig.update_yaxes(range=[-4, 4])
-fig.update_layout(width=800, height=500, showlegend=False, template="none",
-                   plot_bgcolor="white", yaxis2_showgrid=False, xaxis2_showgrid=False)
-
-st.plotly_chart(fig)
\ No newline at end of file
diff --git a/Book4_Ch07_Python_Codes/Streamlit_Bk4_Ch7_02.py b/Book4_Ch07_Python_Codes/Streamlit_Bk4_Ch7_02.py
deleted file mode 100644
index a13f86e..0000000
--- a/Book4_Ch07_Python_Codes/Streamlit_Bk4_Ch7_02.py
+++ /dev/null
@@ -1,61 +0,0 @@
-# -*- coding: utf-8 -*-
-"""
-Created on Mon Sep 12 21:19:47 2022
-
-@author: Work
-"""
-
-import pandas as pd
-import plotly.graph_objs as go
-import streamlit as st
-import numpy as np
-
-with st.sidebar:
-    num = st.slider('Number of points for each dimension',
-                    max_value = 20,
-                    min_value = 10,
-                    step = 1)
-    
-x1 = np.linspace(0,1,num)
-x2 = x1
-x3 = x1
-
-xx1,xx2,xx3 = np.meshgrid(x1,x2,x3)
-
-x1_ = xx1.ravel()
-x2_ = xx2.ravel()
-x3_ = xx3.ravel()
-
-#%%
-df = pd.DataFrame({'X': x1_,
-                   'Y': x2_,
-                   'Z': x3_,
-                   'R': (x1_*256).round(),
-                   'G': (x2_*256).round(),
-                   'B': (x3_*256).round()})
-
-trace = go.Scatter3d(x=df.X,
-                      y=df.Y,
-                      z=df.Z,
-                      mode='markers',
-                      marker=dict(size=3,
-                                  color=['rgb({},{},{})'.format(r,g,b) 
-                                         for r,g,b in 
-                                         zip(df.R.values, df.G.values, df.B.values)],
-                                  opacity=0.9,))
-
-data = [trace]
-
-layout = go.Layout(margin=dict(l=0,
-                               r=0,
-                               b=0,
-                               t=0),
-                   scene = dict(
-    xaxis = dict(title='e_1'),
-    yaxis = dict(title='e_2'),
-    zaxis = dict(title='e_3'),),
-)
-
-fig = go.Figure(data=data, layout=layout)
-
-st.plotly_chart(fig)