issue with defining new coordinates with walls

Question

I have been working on this code from Github DDN car acing. I was trying to understand the code and I was thinking to add some complexity by adding some obstacles. I changed the layout. from to. My question here is. How do we generally define the coordinates? As per my existing understanding, Its with defining walls. There is this .py file named walls.

import pygame

class Wall:
    def __init__(self, x1, y1, x2, y2):
        self.x1 = x1
        self.y1 = y1
        self.x2 = x2
        self.y2 = y2
    
    def draw(self, win):
        pygame.draw.line(win, (255,255,255), (self.x1, self.y1), (self.x2, self.y2), 5)

def getWalls():
    walls = []

    wall1 = Wall(12, 451, 15, 130)
    wall2 = Wall(15, 130, 61, 58)
    wall3 = Wall(61, 58, 149, 14)
    wall4 = Wall(149, 14, 382, 20)
    wall5 = Wall(382, 20, 549, 31)
    wall6 = Wall(549, 31, 636, 58)
    wall7 = Wall(636, 58, 678, 102)
    wall8 = Wall(678, 102, 669, 167)
    wall9 = Wall(669, 167, 600, 206)
    wall10 = Wall(600, 206, 507, 214)
    wall11 = Wall(507, 214, 422, 232)
    wall12 = Wall(422, 232, 375, 263)
    wall13 = Wall(375, 263, 379, 283)
    wall14 = Wall(379, 283, 454, 299)
    wall15 = Wall(454, 299, 613, 286)
    wall16 = Wall(613, 286, 684, 238)
    wall17 = Wall(684, 238, 752, 180)
    wall18 = Wall(752, 180, 862, 185)
    wall19 = Wall(862, 185, 958, 279)
    wall20 = Wall(958, 279, 953, 410)
    wall21 = Wall(953, 410, 925, 505)
    wall22 = Wall(925, 505, 804, 566)
    wall23 = Wall(804, 566, 150, 570)
    wall24 = Wall(150, 570, 46, 529)
    wall25 = Wall(46, 529, 12, 451)
    wall27 = Wall(104, 436, 96, 161)
    wall28 = Wall(96, 161, 122, 122)
    wall29 = Wall(122, 122, 199, 91)
    wall30 = Wall(199, 91, 376, 94)
    wall31 = Wall(376, 94, 469, 100)
    wall32 = Wall(469, 100, 539, 102)
    wall33 = Wall(539, 102, 585, 121)
    wall34 = Wall(585, 121, 585, 139)
    wall35 = Wall(585, 139, 454, 158)
    wall36 = Wall(454, 158, 352, 183)
    wall37 = Wall(352, 183, 293, 239)
    wall38 = Wall(293, 239, 294, 318)
    wall39 = Wall(294, 318, 361, 357)
    wall40 = Wall(361, 357, 490, 373)
    wall41 = Wall(490, 373, 671, 359)
    wall42 = Wall(671, 359, 752, 300) #
    wall43 = Wall(752, 300, 812, 310)#
    wall44 = Wall(812, 310, 854, 369)
    wall45 = Wall(854, 369, 854, 429)
    wall46 = Wall(854, 429, 754, 483)
    wall47 = Wall(754, 483, 192, 489)
    wall48 = Wall(192, 489, 104, 436)

    walls.append(wall1)
    walls.append(wall2)
    walls.append(wall3)
    walls.append(wall4)
    walls.append(wall5)
    walls.append(wall6)
    walls.append(wall7)
    walls.append(wall8)
    walls.append(wall9)
    walls.append(wall10)
    walls.append(wall11)
    walls.append(wall12)
    walls.append(wall13)
    walls.append(wall14)
    walls.append(wall15)
    walls.append(wall16)
    walls.append(wall17)
    walls.append(wall18)
    walls.append(wall19)
    walls.append(wall20)
    walls.append(wall21)
    walls.append(wall22)
    walls.append(wall23)
    walls.append(wall24)
    walls.append(wall25)

    walls.append(wall27)
    walls.append(wall28)
    walls.append(wall29)
    walls.append(wall30)
    walls.append(wall31)
    walls.append(wall32)
    walls.append(wall33)
    walls.append(wall34)
    walls.append(wall35)
    walls.append(wall36)
    walls.append(wall37)
    walls.append(wall38)
    walls.append(wall39)
    walls.append(wall40)
    walls.append(wall41)
    walls.append(wall42)
    walls.append(wall43)
    walls.append(wall44)
    walls.append(wall45)
    walls.append(wall46)
    walls.append(wall47)
    walls.append(wall48)

    return(walls)

I'm stuck on two problems:

1. I've been trying to figure out how are the coordinates "wall1 = Wall(12, 451, 15, 130)" derived? How do we generally write these coordinates?

2. My idea is I could introduce these obstacles in the updated layout in the same walls.py file. But I have no clue how to define coordinates for these too.