* SPICE netlist
XU1 0 N005 v++ v-- N006 LM741 ;pnba In+)In-)V+)V-)OUT
R1 N005 N009 1k
R2 N006 N005 10k
V1 N009 0 SINE(0 0.2 1k)
V2 v++ 0 12
V3 0 v-- 12
R3 N006 0 1k
XU2 0 N001 v++ v-- N002 LM741 ;pnba In+)In-)V+)V-)OUT
R4 N001 N007 1Meg
R5 N002 N001 10Meg
R6 N002 0 1k
XU3 0 N003 v++ v-- N004 LM741 ;pnba In+)In-)V+)V-)OUT
R7 N003 N008 1k
R8 N004 N003 1Meg
R9 N004 0 1k
V4 N007 0 SINE(0 0.2 1k)
V5 N008 0 SINE(0 0.2 1k)
XU4 0 N010 v++ v-- N011 LM741 ;pnba In+)In-)V+)V-)OUT
R10 N010 N012 1k
R11 N011 N010 10k
V6 N012 0 SINE(0 0.2 1k)
R12 N011 0 10
.include lm741.lib
.tran 5m

* LTspice schematic (.asc)
Version 4
SHEET 1 1600 608
WIRE 144 -288 112 -288
WIRE 320 -288 224 -288
WIRE 624 -288 592 -288
WIRE 800 -288 704 -288
WIRE -720 -256 -720 -272
WIRE -336 -256 -368 -256
WIRE -160 -256 -256 -256
WIRE 0 -208 -64 -208
WIRE 112 -208 112 -288
WIRE 112 -208 80 -208
WIRE 144 -208 112 -208
WIRE 480 -208 416 -208
WIRE 592 -208 592 -288
WIRE 592 -208 560 -208
WIRE 624 -208 592 -208
WIRE 320 -192 320 -288
WIRE 320 -192 208 -192
WIRE 800 -192 800 -288
WIRE 800 -192 688 -192
WIRE -480 -176 -544 -176
WIRE -368 -176 -368 -256
WIRE -368 -176 -400 -176
WIRE -336 -176 -368 -176
WIRE 144 -176 112 -176
WIRE 320 -176 320 -192
WIRE 624 -176 592 -176
WIRE 800 -176 800 -192
WIRE -160 -160 -160 -256
WIRE -160 -160 -272 -160
WIRE -720 -144 -720 -176
WIRE -720 -144 -800 -144
WIRE -336 -144 -368 -144
WIRE -160 -144 -160 -160
WIRE -64 -144 -64 -208
WIRE 416 -144 416 -208
WIRE -720 -128 -720 -144
WIRE 112 -128 112 -176
WIRE 592 -128 592 -176
WIRE -800 -112 -800 -144
WIRE -544 -112 -544 -176
WIRE -368 -96 -368 -144
WIRE 320 -64 320 -96
WIRE 800 -64 800 -96
WIRE -160 -32 -160 -64
WIRE -64 -32 -64 -64
WIRE 416 -32 416 -64
WIRE -720 -16 -720 -48
WIRE -544 0 -544 -32
WIRE -352 48 -384 48
WIRE -176 48 -272 48
WIRE -496 128 -560 128
WIRE -384 128 -384 48
WIRE -384 128 -416 128
WIRE -352 128 -384 128
WIRE -176 144 -176 48
WIRE -176 144 -288 144
WIRE -352 160 -384 160
WIRE -176 160 -176 144
WIRE -560 192 -560 128
WIRE -384 208 -384 160
WIRE -176 272 -176 240
WIRE -560 304 -560 272
FLAG -800 -112 0
FLAG -544 0 0
FLAG -368 -96 0
FLAG -160 -32 0
FLAG -720 -16 v--
FLAG -720 -272 v++
FLAG -304 -192 v++
FLAG -304 -128 v--
FLAG -64 -32 0
FLAG 112 -128 0
FLAG 320 -64 0
FLAG 176 -224 v++
FLAG 416 -32 0
FLAG 592 -128 0
FLAG 800 -64 0
FLAG 656 -224 v++
FLAG 656 -160 v--
FLAG -560 304 0
FLAG -384 208 0
FLAG -176 272 0
FLAG -320 112 v++
FLAG -320 176 v--
FLAG 176 -160 v--
SYMBOL OpAmps\\opamp2 -304 -224 R0
SYMATTR InstName U1
SYMATTR Value LM741
SYMBOL res -384 -192 R90
SYMATTR InstName R1
SYMATTR Value 1k
SYMBOL res -240 -272 R90
SYMATTR InstName R2
SYMATTR Value 10k
SYMBOL voltage -544 -128 R0
SYMATTR InstName V1
SYMATTR Value SINE(0 0.2 1k)
SYMBOL voltage -720 -272 R0
SYMATTR InstName V2
SYMATTR Value 12
SYMBOL voltage -720 -144 R0
SYMATTR InstName V3
SYMATTR Value 12
SYMBOL res -176 -160 R0
SYMATTR InstName R3
SYMATTR Value 1k
SYMBOL OpAmps\\opamp2 176 -256 R0
SYMATTR InstName U2
SYMATTR Value LM741
SYMBOL res 96 -224 R90
SYMATTR InstName R4
SYMATTR Value 1Meg
SYMBOL res 240 -304 R90
SYMATTR InstName R5
SYMATTR Value 10Meg
SYMBOL res 304 -192 R0
SYMATTR InstName R6
SYMATTR Value 1k
SYMBOL OpAmps\\opamp2 656 -256 R0
SYMATTR InstName U3
SYMATTR Value LM741
SYMBOL res 576 -224 R90
SYMATTR InstName R7
SYMATTR Value 1k
SYMBOL res 720 -304 R90
SYMATTR InstName R8
SYMATTR Value 1Meg
SYMBOL res 784 -192 R0
SYMATTR InstName R9
SYMATTR Value 1k
SYMBOL voltage -64 -160 R0
SYMATTR InstName V4
SYMATTR Value SINE(0 0.2 1k)
SYMBOL voltage 416 -160 R0
SYMATTR InstName V5
SYMATTR Value SINE(0 0.2 1k)
SYMBOL OpAmps\\opamp2 -320 80 R0
SYMATTR InstName U4
SYMATTR Value LM741
SYMBOL res -400 112 R90
SYMATTR InstName R10
SYMATTR Value 1k
SYMBOL res -256 32 R90
SYMATTR InstName R11
SYMATTR Value 10k
SYMBOL voltage -560 176 R0
SYMATTR InstName V6
SYMATTR Value SINE(0 0.2 1k)
SYMBOL res -192 144 R0
SYMATTR InstName R12
SYMATTR Value 10