Triple interaction of categorical variables in xtreg (Stata14)

[Israel Escudero]

Hello. I have some doubts about the interpretation of the result of a regression when I use a triple interaction of categorical variables as independent variable. In my case, variable1 has three categories, variable 2 and variable 3 are dummies. This are the results:

 variable1#variable2#variable3 |
                                                        1 0 0  |          0  (base)
                                                        1 0 1  |          0  (base)
                                                        1 1 0  |  -2.927292   1.539743    -1.90   0.057    -5.945132    .0905486
                                                        1 1 1  |  -1.823786   1.413591    -1.29   0.197    -4.594373    .9468023
                                                        2 0 0  |          0  (base)
                                                        2 0 1  |          0  (base)
                                                        2 1 0  |  -.0424758    2.66852    -0.02   0.987    -5.272679    5.187727
                                                        2 1 1  |   1.546441   2.684047     0.58   0.565    -3.714195    6.807077
                                                        3 0 0  |          0  (base)
                                                        3 0 1  |          0  (base)
                                                        3 1 0  |   .4066601    3.23689     0.13   0.900    -5.937528    6.750848
                                                        3 1 1  |  -1.389242   1.891416    -0.73   0.463    -5.096348    2.317865
                                                               |

The results show 6 base levels (1 0 0/1 0 1/2 0 0/ 2 0 1/3 0 0/3 0 1). The question is what is the base level for each of the interactions. In general, I have doubts about how to interpret the results with interactions of categorical variables.
Thank you very much in advance.
IE