A for awesome wrote:Well, here's a dependent H-B that probably has no input or output:

It definitely has a usable output; the input might be slightly more difficult:

`x = 63, y = 72, rule = LifeHistory`

38.2A$38.A$39.3A2.2B$41.A3B2A$43.2B2A2B6.2A$43.6B6.A$37.2A3.7B3.BA.A$

38.A4.6B3.B2A5.A$38.A.AB.10B5.3A$39.2AB.10B4.A$41.12B4.2A$41.18B$41.

16B$31.2A8.18B$32.A9.17B$32.A.AB4.19B$33.2AB.20B.B2A$35.21B2.BA.A$35.

20B6.A$36.19B6.2A$35.20B$33.22B$31.24B$31.2BC22B$30.3BCBC20B$31.2B3C

4B.13B4.A$12.2A16.5BC4B2.12B3.A.A$12.A2.A13.10B2.9B.2B4.A2.A$13.3A12.

8B5.11B3.3A3.A$7.2A18.8B4.15BAB2.3A$7.A.A5.3A8.8B.19B4A$2.A6.A4.A2.AB

4.13BD17B.B2.A$2.3A4.2A3.2A2B4.13B2D17B2AB2A$5.A4.B4.B.3B2.12B2D15B3.

AB3.2A$4.2A4.2B2.7B.13BD15B4.2A.A2.A$4.10B.21BD14B5.A.A.A$6.30B3.11B

6.A2.A$5.24B2.4B5.2B.7B7.2A$5.22B3.4B10.4B$6.20B3.4B13.3B$7.20B.4B13.

B2A3B$7.24B15.A2.A.A$10.20B17.3A.3A$9.20B21.A3.A$9.19B19.2A.A2.2A$8.

19B20.A.A$4.17B.4B$3.2A15B.4B$3.2A19B$4.19B$6.16B$5.16B$4.4B.11B$4.3B

.11B$2.2AB3.10B$.A.AB3.9B$.A5.10B2.B$2A3.B.10B.B2A$4.2A13B2A$4.2A11B.

2B$5.12B$5.3B.9B$8.11B$8.12B$9.7B.4B$10.7B.4B$8.B.19B$7.2A3B2A11BD4B$

7.2AB.B2A9B3D4B$8.B2.12BDBD4B$12.11BD6B$13.B2.2B2.10B!

EDIT: This might be a potential route of attack, if the white object can be inserted:

`x = 63, y = 72, rule = LifeHistory`

38.2A$38.A$39.3A2.2B$41.A3B2A$43.2B2A2B6.2A$43.6B6.A$37.2A3.7B3.BA.A$

38.A4.6B3.B2A5.A$38.A.AB.10B5.3A$39.2AB.10B4.A$41.12B4.2A$41.18B$26.C

14.16B$24.BCB4.2A8.18B$22.3BCB5.A9.17B$20.5BC6.A.AB4.19B$20.3BCB3C5.

2AB.20B.B2A$20.3BC2BCB7.21B2.BA.A$21.2B3C3B6.20B6.A$20.9B7.19B6.2A$

20.8B7.20B$20.8B5.22B$18.10B2.25B$17.16BD22B$16.7B2A8BDBD20B$16.6BABA

8B3D4B.13B4.A$17.5B2A11BD4B2.12B3.A.A$13.2A4.20B2.9B.2B4.A2.A$12.A2.A

5.6B.8B5.11B3.3A3.A$7.2A3.3A12.8B4.15BAB2.3A$7.A.A5.3A8.8B.19B4A$2.A

6.A4.A2.AB4.13BD17B.B2.A$2.3A4.2A3.2A2B4.13B2D17B2AB2A$5.A4.B4.B.3B2.

12B2D15B3.AB3.2A$4.2A4.2B2.7B.13BD15B4.2A.A2.A$4.10B.21BD14B5.A.A.A$

6.30B3.11B6.A2.A$5.24B2.4B5.2B.7B7.2A$5.22B3.4B10.4B$6.20B3.4B13.3B$

7.20B.4B13.B2A3B$7.24B15.A2.A.A$10.20B17.3A.3A$9.20B21.A3.A$9.19B19.

2A.A2.2A$8.19B20.A.A$4.17B.4B$3.2A15B.4B$3.2A19B$4.19B$6.16B$5.16B$4.

4B.11B$4.3B.11B$2.2AB3.10B$.A.AB3.9B$.A5.10B2.B$2A3.B.10B.B2A$4.2A13B

2A$4.2A11B.2B$5.12B$5.3B.9B$8.11B$8.12B$9.7B.4B$10.7B.4B$8.B.19B$7.2A

3B2A11BD4B$7.2AB.B2A9B3D4B$8.B2.12BDBD4B$12.11BD6B$13.B2.2B2.10B!